MFC r325834,r325997,326502: Move sys/boot to stand/

This is effectively a direct commit to stable/11, due to differences between
stable/11 and head. Changes to DTS in sys/boot/fdt/dts were often
accompanied by kernel changes. Many of these were also risc-v updates that
likely had many more dependencies to MFC.

Because of this, sys/boot/fdt/dts remains as-is while everything else in
sys/boot relocates to stand/.

r325834: Move sys/boot to stand. Fix all references to new location

r325997: Remove empty directories.

r326502: Document the sys/boot -> stand move in hier.7 and the top-level README.

MFC Loader Fixes 2017q3: r320547,r320553,r321621,r321844,r321969,r321991,
r322037,r322038,r322039,r322040,r322056,r322074,r322542,r322592,r322593,
r322896,r322923,r323671,r322930,r322931,r322932,r322933,r322934,r322935,
r322936,r322937,r322938,r322939,r322941,r323062,r323063,r323064,r323065,
r323100,r323131,r323174,r323258,r323261,r323272,r323367,r323379,r323389,
r323407,r323428,r323436,r323494,r323496,r323497,r323541,r323554,r323589,
r323707,r323867,r323885,r323886,r323895,r323896,r323897,r323905,r323906,
r323907,r323908,r323909,r323952,r323991,r324099,r324558,r326445,r326609,
r326610

This batch includes a special kludge to fix powerpc loader build; <stdlib.h>
was included after <stand.h> there, causing problems with DEBUG_MALLOC bits.
Include <stdlib.h> a little bit earlier to fix the build with the intention
of removing this when eventually libsa silently replaces stdlib.h with
stand.h.

r320547: Link EFI/uboot loaders with -znotext

r320553: Integer underflow in efipart_realstrategy when I/O starts after end
of disk

r321621: Always set the receive mask in loader.efi.

r321844: Clean up style in print_state(..) and pager_printf(..)

r321969: Fix the return types for printf and putchar to match their libc

r321991: Revert r321969

r322037: Add stpcpy and stpncpy to libstand

r322038: Add definitions and utilities for EFI drivers

r322039: Move EFI ZFS functions to libefi

r322040: Add EFI utility functions to libefi

r322056: Move EFI fmtdev functionality to libefi

r322074: libefi/time.c cstyle cleanup

r322542: loader.efi: repace XXX with real comments in trap.c

r322592: Remove unused defines.

r322593: Define proposed GUID for FreeBSD boot loader variables.

r322896: Make spinconsole platform independent and hook it up into EFI
loader

r322923: Hide length of geli passphrase during boot.

r323671: Fix language used in the r322923.

r322930: Move efi_main into efi/loader

r322931: Cleanup efi_main return type

r322932: Use the loader.efi conventions for the various EFI tables.

r322933: No need for MK_ZFS around these: they are by their nature only
active when MK_ZFS is true.

r322934: _STAND is sometimes defined on the command line. Make the define
here match.

r322935: Fix warnings due to type mismatch.

r322936: Remove useless 'static' for an enum definition.

r322937: Forward declare struct dsk to avoid warnings when building libi386.

r322938: Link in libefi for boot1

r322939: Use efi_devpath_str for debug path info.

r322941: Eliminate redunant device path matching.

r323062: Make efichar.c routines available to libefi.

r323063: boot1.efi: print more info about where boot1.efi is loaded from

r323064: Exit rather than panic for most errors.

r323065: Save where we're booted from

r323100: libstand: nfs_readlink() should return proper return code

r323131: Revert r322941: Eliminate redundant device matching functions

r323174: Fix loader bug causing too many pages allocation when bootloader
is U-Boot

r323258: ucs2len

r323261: Fix armv6 build

r323272: Be consistent and do return (1);

r323367: Mark init_chroot and init_script variables as deprecated.

r323379: It's been pointed out that init_script at least is useful w/o

r323389: loader.efi: chain loader should provide proper device handle

r323407: boot1 generate-fat: generate all templates at once

r323428: r323389 breaks the kernel build when WITHOUT_ZFS is defined in
src.conf

r323436: boot1: remove BOOT1_MAXSIZE default value

r323494: loader should support large_dnode

r323496: libstand: tftp_open() can leak pkt on error

r323497: libefi: efipart_open should check the status from disk_open

r323541: libefi: efipart_realstrategy rsize pointer may be NULL

r323554: Increase EFI boot file size frok 128k to 384k

r323589: loader: biosmem.c cstyle cleanup

r323707: loader: biosmem allocate heap just below 4GB

r323867: libefi: devicename.c cleanups

r323885: libefi: efi_devpath_match() should return bool

r323886: libefi: efipart.c should use calloc()

r323895: libefi: efi_devpath_match local len should be unsigned

r323896: r323885 did miss efilib.h update

r323897: efilib.h: typo in structure member description

r323905: libefi: pdinfo_t pd_unit and pd_open should be unsigned

r323906: libefi: efipart_strategy() should return ENXIO when there is no
media

r323907: libefi: efipart.c cstyle fix for efipart_print_common()

r323908: libefi: efipart_hdinfo_add_filepath should check strtol result

r323909: libefi: define EISA PNP constants

r323952: After the r317886 support for TFTP and NFS can be enable
simultaneously.

r323991: libefi: efipart_floppy() will should not pass acpi pointer if the
HID test fails

r324099: Compile loader as Little-Endian on PPC64/POWER8

r324558: Define prototype for exit and ensure references

r326445: Fix random() and srandom() prototypes to match the standard.

r326609: Make putenv and getenv match the userland definition

r326610: Fix random() prototype to match the system.

PR: 219000 221001 222215
Relnotes: yes ("The length of the geli passphrase is hidden during boot")

Add definitions and utilities for EFI drivers

This patch adds definitions and utility code for creating EFI drivers
using the EFI_DRIVER_BINDING_PROTOCOL.

Submitted by: Eric McCorkle
Differential Revision: https://reviews.freebsd.org/D11852