Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

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

Remove bus space fdt for MIPS.

This was originall done by kan@.

Submitted by: Stanislav Galabov <sgalabov@gmail.com>
Reviewed by: kan
Differential Revision: https://reviews.freebsd.org/D5184

Retire machine/fdt.h as a header used by MI code, as its function is now
obsolete. This involves the following pieces:
- Remove it entirely on PowerPC, where it is not used by MD code either
- Remove all references to machine/fdt.h in non-architecture-specific code
(aside from uart_cpu_fdt.c, shared by ARM and MIPS, and so is somewhat
non-arch-specific).
- Fix code relying on header pollution from machine/fdt.h includes
- Legacy fdtbus.c (still used on x86 FDT systems) now passes resource
requests to its parent (nexus). This allows x86 FDT devices to allocate
both memory and IO requests and removes the last notionally MI use of
fdtbus_bs_tag.
- On those architectures that retain a machine/fdt.h, unused bits like
FDT_MAP_IRQ and FDT_INTR_MAX have been removed.

Merge Perforce changeset 219925 to head:

Provided a bus_space implementation for FDT, modelled on
bus_space_generic, but with a local version of the map address
routine that does a P->V translation, as is the case with NLM's
similar routine for XLP. It's not clear to me that this is the
right solution -- possibly this belongs in simplebus -- however,
it is sufficient to get the DE4 LED driver working.

Sponsored by: DARPA, AFRL

Support for booting XLP using FDT.

- update xlp_machdep.c to read arguments from FDT if FDT support is
compiled in.
- define rmi_uart_bus_space, and use it as fdtbus_bs_tag
- update conf files for FDT support
- add default dts file xlp-basic.dts

FDT support for MIPS.

Add architecture specific files needed to compile MIPS with
flattened device tree support.