MFC r341101, r341231, r341276, r341329, r341433, r341780, r342054-r342055,
r342721, r342742, r342840, r343008, r343225

r341101:
powerpcspe: Don't crash the loader on ubldr with SPE instructions.

-msoft-float seems to be insufficient for disabling the SPE on powerpcspe.
Force it off with -mno-spe as well. This prevents a crash in ubldr on
powerpcspe.

r341231:
loader: command_bcache() should print unsigned values

All bcache counters are unsigned.

r341276:
When handling CMD_CRIT error set command_errmsg to NULL after we dump it out,
so that it does not result in error message printed twice.

OK load doodoo
can't find 'doodoo'
can't find 'doodoo'
OK

r341329:
loader.efi: fix EFI getchar() for multiple consoles

This fix is ported from illumos (issue #9970), the analysis and initial
implementation was done by John Levon.

See also: https://www.illumos.org/issues/9970

Currently, efi_cons_getchar() will wait for a key. While this seems to make
sense, the implementation of getchar() in common/console.c will loop across
getchar() for all consoles without doing ischar() first.

This means that if we've configured multiple consoles, we can't input into
the serial, as getchar() will be sat waiting for input only from efi_console.c

This patch does implement a bit more generic key buffer to support
translation of input keys, and we use generic efi_readkey() to reduce
duplication from calls from getchar() and poll().

r341433:
Move inclusion of src.opts.mk later.

src.opts.mk includes bsd.own.mk. This in turn defines CTFCONVERT_CMD
depending on the MK_CTF value. We then set MK_CTF to no, which has no
real effect. The solution is to set all the MK_foo values before
including src.opts.mk.

This should stop the cdboot binary from exploding in size for releases
built WITH_CTF=yes in src.conf.

r341780:
powerpc/ubldr: Teach powerpc's ubldr to boot 64-bit kernels

This is just a copy of powerpc/ofw's ppc64_elf_freebsd.c modified to fit
ubldr's boot format.

r342054:
Print an error message in efi_main.c if we can't allocate memory for the heap

With the default Qemu parameters, only 128MB RAM gets given to a VM. This causes
the loader to be unable to allocate the 64MB it needs for the heap. This change
makes the cause of the error more obvious.

r342055:
Cast error message in efi_main.c to CHAR16* to avoid build error

r342721:
loader.efi: update memmap command to recognize new attributes

Also move memory type to string translation to libefi for later use.

r342742:
loader.efi: efi variable rework and lsefi command added

This update does add diag and debug capabilities to interpret the efi
variables, configuration and protocols (lsefi).

The side effect is that we add/update bunch of related headers.

r342840:
Create MK_LOADER_VERBOSE and connect it to ELF_VERBOSE in the loader
code.

r343008:
Add Dell Chromebook to the list of devices with E820 extmem quirk enabled

Just like for Acer C270 chromebook the E820 extmem workaround is required for
FreeBSD to boot on Dell chromebook.

r343225:
Unbreak mip64 build after r328437

Add exit and getchar functions to beri/boot2 code. They are required by
panic_action functin introduced in r328437

PR: 18498, 204916

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.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Enable warnings in EFI boot code

Set WARNS if not set for EFI boot code and fix the issues highlighted by
setting it.

Most components are set to WARNS level 6 with few being left at lower
levels due to the amount of changes needed to fix at higher levels.

Error types fixed:
* Missing / invalid casts
* Missing inner structs
* Unused vars
* Missing static for internal only funcs
* Missing prototypes
* Alignment changes
* Use of uninitialised vars
* Unknown pragma (intrinsic)
* Missing types etc due to missing includes
* printf formatting types

Reviewed by: emaste (in part)
MFC after: 2 weeks
X-MFC-With: r293268
Sponsored by: Multiplay
Differential Revision: https://reviews.freebsd.org/D4839

Sync the EFI headers with version 1.10.14.62 of the Intel sample EFI
implementation. This re-introduces C99 style comments that previously
were replaced by original C comments.

An almost mechanical sweep to replace C++ style comments with C
style comments. This is not an attempt to conform to style(9).
Such has lower priority.

First approximation of an ia64 EFI loader. Not functional.