Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove support for SKI: HP's Itanium simulator. It's pretty much not
used, serves very little value given that FreeBSD runs on real H/W
for a long time.
Note that SKI is open-source (see http://ski.sourceforge.net), so
if there's interest and value again, then this code can be revived.

Discussed with: jhb

Use a non-standard page size that is supported.

Provide groundwork for 32-bit binary compatibility on non-x86 platforms,
for upcoming 64-bit PowerPC and MIPS support. This renames the COMPAT_IA32
option to COMPAT_FREEBSD32, removes some IA32-specific code from MI parts
of the kernel and enhances the freebsd32 compatibility code to support
big-endian platforms.

Reviewed by: kib, jhb

- Use "device\t" and "options \t" for consistency.

Don't forget to create opt_agp.h on ia64, which also uses agp(4).

Move "device splash" back to MI NOTES and "files", it's MI.

Move more MD devices and options out of MI NOTES.

The VGA_DEBUG option only exists on {amd64,i386,ia64}.
Also remove 'device io' from amd64 NOTES; DEFAULTS takes care of it.

Remove sio(4) and related options from MI files to amd64, i386
and pc98 MD files. Remove nodevice and nooption lines specific
to sio(4) from ia64, powerpc and sparc64 NOTES. There were no
such lines for arm yet.
sio(4) is usable on less than half the platforms, not counting
a future mips platform. Its presence in MI files is therefore
increasingly becoming a burden.

EISA bus ia64 systems don't exist in reality. I'm told they may exist in
theory, but that it was OK to remove from NOTES.

OK'd by: marcel

- Allow duplicate "machine" directives with the same arguments.
- Move existing "machine" directives to DEFAULTS.

Remove acpi_perf from {ARCH}/conf/NOTES, to make tinderbox happy.

Reported by: tinderbox
Inspired by: acpi_perf build structure removal commit

Build cpufreq and acpi_perf on platforms that are likely to be able to
use them.

Catch up with the drive-by renaming of IA32 to COMPAT_IA32. Missed
11 days ago when all the other places were fixed and finally caught
by the tinderbox run...

Fix typo in comment. While here, end the sentence with a period and
remove the empty line between the fdc and sio devices. The empty
line suggests that the comment applies to fdc only while it applies
to all following devices and options.

Typo spotted by: ru@

filter out the fdc(4) and sio(4) devices and corresponding options.
Note that cy(4) uses COM_MULTIPORT, so we need to keep that option.

Introduce IA64_ID_PAGE_{MASK|SHIFT|SIZE} and LOG2_ID_PAGE_SIZE. The
latter is a kernel option for IA64_ID_PAGE_SHIFT, which in turn
determines IA64_ID_PAGE_MASK and IA64_ID_PAGE_SIZE.

The constants are used instead of the literal hardcoding (in its
various forms) of the size of the direct mappings created in region
6 and 7. The default and probably only workable size is still 256M,
but for kicks we use 128M for LINT.

Change LOG2_PAGE_SIZE from 14 to 15 bits. This will cause the CTASSERT
in vm_page.h to be reached and thus slightly increases the overall
coverage of LINT on ia64.

Add the bits for a LINT kernel. It has been verified to compile. We
may need to polish this.