Merge MIPS platform support to 8-STABLE.

Merge MIPS platform support to 8-STABLE.

This commit merges the MIPS platform changes that was now stable in
-CURRENT into 8-STABLE. The MIPS changesets are too many (~400) to list
here. But the changesets merged in this commit that affect other platforms
are summarized below:

r204635 : (changes to sys/dev/hwpmc, lib/libpmc, sys/sys/pmc.h)
Add support for hwpmc(4) on the MIPS 24K, 32 bit, embedded processor.

r205845: (changes to sys/modules/Makefile)
Fix for building modules on mips and arm.

r204031: (changes to sys/kern/link_elf_obj.c)
printf fix, as part of kernel module support for MIPS.

r206404: (changes to sys/arm/include/bus.h)
Add BUS_SPACE_UNRESTRICTED and define it to be ~0, just like all the
other platforms - for arm and mips.

r206819: (changes to sys/vm/)
Add VMFS_TLB_ALIGNED_SPACE option and kmem_alloc_nofault_space(), which
is used to allocate kernel stack address on MIPS.

r208165, r211087: (sys/kern/subr_smp.c, sys/kern/sched_ule.c)
Enable ULE scheduler for MIPS, Fix for an issue in SMP when 32 cpus are
enabled.

r208659: (sys/{ia64/ia64,mips/mips,sun4v/sun4v}/pmap.c)
Simplify the inner loop of get_pv_entry()

r208794: (changes to sys/vm/)
Make vm_contig_grow_cache() extern, and use it when vm_phys_alloc_contig()
fails to allocate MIPS page table pages.

r210327:  (changes to sys/vm/)
Support for MIPS page table page allocation.  Add a new function 'vm_page_t
vm_page_alloc_freelist(int flind, int order, int req)' to vm/vm_page.c to
allocate a page from a specified freelist, and other related changes.

Reviewed by:	alc(vm changes only)
Approved by:	kib(re), alc(vm), imp(mips), jmallett(mips), gnn(mips pmc)

git-svn-id: svn://svn.freebsd.org/base/stable/8@215938 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f