sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

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

Set internal error returns for OF_peer(), OF_child(), and OF_parent() to
zero, matching the IEEE 1275 standard. Since these internal error paths
have never, to my knowledge, been taken, behavior is unchanged.

Reported by: gonzo
MFC after: 2 weeks

sys/dev: 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.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Change OF_interpret() to also take an array of cell_t (missed in r209801).

Reviewed by: nwhitehorn

Change the argument type to OF_call_method to take an array of cell_t
instead of unsigned longs to prepare for platforms where they are not
the same.

Prepare and extend OFW layer for FDT support.

o Let OFW_INIT() and OF_init() return status value.

o Provide helper routines for 'compatible' property handling.

o Only compile OF and OFW code, which is relevant in FDT scenario.

o Other minor cosmetics

Reviewed by: imp
Sponsored by: The FreeBSD Foundation

Pull OF_quiesce() out of the MI Open Firmware layer and entirely into
PPC ofw_machdep.c, in recognition of its state as a machine specific hack.

Requested by: marius

On PowerMac11,2 and (presumably) PowerMac12,1, we need to quiesce the
firmware in order to take over control of the SMU. Without doing this,
the firmware background process doing fan control will run amok as we
take over the system and crash the management chip.

This is limited to these two machines because our kernel is heavily
dependent on firmware accesses, and so quiescing firmware can cause
nasty problems.

With r205496 in place we should ensure that nargs and nreturns are always
set to sane values as they no longer default to 0, otherwise some OFW
implementation might copy in or out arguments not based on what the actual
function takes but what ever stack garbage nargs and nreturns supply.

Reviewed by: nwhitehorn

Do not declare the various OFW command buffers static. It does not
appear to be necessary on either sparc64 or powerpc, and is a
concurrency nightmare.

Reviewed by: marius

Fix style.

strict kobj signatures: some ofw_setprop fixes

propname parameter is const

Reviewed by: imp, current@
Approved by: jhb (mentor)

Unbreak OF_interpret() and its standard implementation after r186347.

Modularize the Open Firmware client interface to allow run-time switching
of OFW access semantics, in order to allow future support for real-mode
OF access and flattened device frees. OF client interface modules are
implemented using KOBJ, in a similar way to the PPC PMAP modules.

Because we need Open Firmware to be available before mutexes can be used on
sparc64, changes are also included to allow KOBJ to be used very early in
the boot process by only using the mutex once we know it has been initialized.

Reviewed by: marius, grehan