Add new code to read and parse cpu identification data using the new CPUID
mechanism defined for armv7 (and also present on some armv6 chips including
the arm1176 used on rpi).  The information is parsed into a global cpuinfo
structure, which will be used by (upcoming) new cache and tlb maintenance
code to handle cpu-specific variations of the maintence sequences.

Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
              Michal Meloun <meloun@miracle.cz
Add new TLB and cache maintainence functions for armv6 and armv7.  These
are inline functions that handle all the routine maintenance operations
except the flush-all and invalidate-all routines which are required only
during early kernel init.

These inline functions should be very much faster than the old mechanism
that involved jumping through the big cpufuncs table, especially for
common operations such as invalidating a single TLB entry.  Note that
nothing is calling these yet, this just is just required infrastructure
for upcoming changes to the pmap-v6 code.
Eliminate an unused macro whose name clashes now with a function in the
new cpu-v6.h.  This should have been part of r276334.
Add cache maintenance functions which will be used by startup code to
initially set up the MMU.  Some day they may also be useful as part of
suspend/resume handling, when we get better at power management.

Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
              Michal Meloun <meloun@miracle.cz
Fix a "decl is not a prototype" error noticed by gcc (but not clang).
sysctl: don't modify oid_running for static nodes

It is necessary to prevent nodes from being destroyed while used, but static
ones cannot be destroyed.
Fix the following -Werror warning from clang 3.5.0, while building
rtld-elf for powerpc 32 bit:

libexec/rtld-elf/powerpc/reloc.c:486:6: error: taking the absolute value of unsigned type 'Elf_Addr' (aka 'unsigned int') has no effect [-Werror,-Wabsolute-value]
        if (abs(offset) < 32*1024*1024) {     /* inside 32MB? */
            ^
libexec/rtld-elf/powerpc/reloc.c:486:6: note: remove the call to 'abs' since unsigned values cannot be negative
        if (abs(offset) < 32*1024*1024) {     /* inside 32MB? */
            ^~~
1 error generated.

Cast 'offset' to int, since that was intended, and should be safe to do
on architectures with 32-bit two's complement ints.

Reviewed by:	kib
Differential Revision: https://reviews.freebsd.org/D1387
- Const'ify the ahci_ids table.
- Use DEVMETHOD_END.
- Use NULL instead of 0 for pointers.

MFC after:	3 days
Correct naming of sysctl pmtud_blackhole_activated_min_mss.

Clarify some statements around PMTUD blackhole detection to make
the behavior more clear in the man page.

Submitted by:	Mikhail <mp@lenta.ru>
MFC after:	2 weeks
In contrib/binutils/gas/config/tc-ppc.c, fix a few -Wformat-security
warnings.

MFC after:	3 days
r245508 modified the NFS client's Setattr RPC to
use VA_UTIMES_NULL to indicate whether it should
set the time to the current tod on the server.
This had the side effect of making the NFS client
use the client's timestamp for exclusive create,
starting with FreeBSD9.2.
Unfortunately a bug in some Solaris NFS servers
causes these servers to return NFS_OK to the
Setattr RPC done during exclusive create, but not
actually set the file's mode, leaving the file's
mode == 0.
This patch restores the NFS client's behaviour to
use the server's tod for the exclusive open's
Setattr RPC, to avoid the Solaris server bug and
to restore the pre-FreeBSD9.2 NFS behaviour.

Discussed on:	freebsd-fs
PR:	186293
MFC after:	3 months
Update comments (r4 is not used anywhere), use non-profiling entry macros.
Don't use a sub-device/-vendor wildcard for probing MCS9922 as other
chips with the same device and vendor IDs actually may provide different
functionality. While at it, canonicalize the description to match other
MosChip UARTs.

PR:		186891
MFC after:	3 days
Merge remote-tracking branch 'freebsd/master' into hardened/current/master
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/unstable