sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

[PowerPC64LE] Fix RTAS LE calls in pseries.

Similar to OPAL calls, switch to big endian to do calls to RTAS.

(Missed this one when I was doing the bulk commit of PowerPC64LE support.)

Sponsored by: Tag1 Consulting, Inc.

powerpc: clean up empty lines in .c and .h files

sys/powerpc: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

As <machine/pmap.h> is included from <vm/pmap.h>, there is no need to
include it explicitly when <vm/pmap.h> is already included.

Reviewed by: alc, kib
Differential Revision: https://reviews.freebsd.org/D5373

Use setjmp() instead of the identical-except-for-having-a-wrong-prototype
setfault() when testing for faults. This should also help the compiler
do the right thing with this complicated-to-optimize function.

Allow use of a pre-instantiated RTAS as well as a self-instantiated one. This
lets the kernel boot on RTAS-based systems by being kexec'ed from Linux.

Make RTAS calls, which call setfault() to recover from machine checks,
preserve any existing fault buffer. RTAS calls are meant to be safe from
interrupt context (and are indeed used there to implement the xics PIC
drvier). Without this, calling into RTAS in interrupt context would have
the effect of clearing any existing onfault state of the interrupted
thread, potentially leading to a panic.

Use a spin lock instead of a mutex to gate RTAS. This is required if RTAS
calls are involved in interrupt handling.

Approved by: re (kib)

Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.

This means that their use is restricted to a single C file.

Add better error handling for RTAS calls. These can potentially cause
machine checks (e.g. invalid PCI configuration cycles), but these can
be caught and recovered from. This change also the RTAS PCI driver to
work without modification as a replacement for the Grackle driver on
Grackle-based Powermacs.

MFpseries:
Renovate and improve the AIM Open Firmware support:
- Add RTAS (Run-Time Abstraction Services) support, found on all IBM systems
and some Apple ones
- Improve support for 32-bit real mode Open Firmware systems
- Pull some more OF bits over from the AIM directory
- Fix memory detection on IBM LPARs and systems with more than one /memory
node (by andreast@)