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

Add fman and dpaa fixups for powerpc fdt

Obtained from: Semihalf

Remove fdt_pic_table code from MIPS, PowerPC, and x86, as it is no longer
used by anything. The equivalent functionality is provided by the PIC drivers
themselves on PowerPC and this is a no-op on MIPS and x86.

Standards-conformance and code deduplication:
- Use bus reference phandles in place of FDT offsets as IRQ domain keys
- Unify the identical macio/fdt/mambo OpenPIC drivers into one
- Be more forgiving (following ePAPR) about what we need from the device
tree to identify an OpenPIC
- Correctly map all IRQs into an interrupt domain
- Set IRQ_*_CONFORM for interrupts on an unknown PIC type instead of
failing attachment for that device.

Fix OF_finddevice error return value in case of FDT.

According to the open firmware standard, finddevice call has to return
a phandle with value of -1 in case of error.

This commit is to:
- Fix the FDT implementation of this interface (ofw_fdt_finddevice) to
return (phandle_t)-1 in case of error, instead of 0 as it does now.
- Fix up the callers of OF_finddevice() to compare the return value with
-1 instead of 0 to check for errors.
- Since phandle_t is unsigned, the return value of OF_finddevice should
be checked with '== -1' rather than '<= 0' or '> 0', fix up these cases
as well.

Reported by: nwhitehorn

Reviewed by: raj
Approved by: raj, nwhitehorn

Introduce PowerPC-specific helper routines for FDT.

Reviewed by: imp
Sponsored by: The FreeBSD Foundation