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/

ipmi: Remove unused devclass arguments to DRIVER_MODULE.

[PowerPC64] Fix OPAL IPMI driver

This change fixes a couple of issues with OPAL IPMI driver and
implements a mechanism to detect timeouts and discard old messages left
in receive queue, to avoid old messages from being confused with the
reply of new ones.

Reviewed by: jhibbits
Sponsored by: Eldorado Research Institute (eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D24185

Extract eventfilter declarations to sys/_eventfilter.h

This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.

EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).

As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions. The remainder of the patch addresses
adding appropriate includes to fix those files.

LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).

No functional change (intended). Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed. __FreeBSD_version has been bumped.

ipmi: Fixes for ipmi_opal(powernv)

* Crank the OPAL state machine during the receive loop, to make sure the
pollers are executed
* Add a proper detach function, so the module can be unloaded and reloaded
at runtime.

It still doesn't reliably work 100% of the time on POWER9, and it appears
timing and/or cache related. It may work on POWER8 now.

MFC after: 2 weeks

ipmi/opal: Enable polled mode and proper callback

Fix a NULL dereference that would occur any time an ioctl() was done, due to a
missing ipmi_enqueue_request callback. Just use the default for now, until we
decide to properly enable IPMI interrupts.

Reported by: kbowling

Support building IPMI as a module on powerpc64

This still only supports IPMI via OPAL on powerpc64, but now it can be tested
with a GENERIC kernel.