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

Allow us to be told about memory past the first 4GB point, but ignore it.
This allows, for example, UEFI pass a memory map with some ram in this
region, but for us to ignore it. This is the case when running under the
qemu virt machine type.

Sponsored by: ABT Systems Ltd

Implement OF_decode_addr() for arm. Move most of powerpc's implementation
into a new function that other platforms can share.

This creates a new ofw_reg_to_paddr() function (in a new ofw_subr.c file)
that contains most of the existing ppc implementation, mostly unchanged.
The ppc code now calls the new MI code from the MD code, then creates a
ppc-specific bus_space mapping from the results. The new arm implementation
does the same in an arm-specific way.

This also moves the declaration of OF_decode_addr() from ofw_machdep.h to
openfirm.h, except on sparc64 which uses a different function signature.

This will help all FDT platforms to set up early console access using
OF_decode_addr().

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.

Initial FDT infrastructure elements for ARM.

Reviewed by: imp
Sponsored by: The FreeBSD Foundation