Patch: SMP support for MIPS

[Neel Natu]

Hi,

I am ready to commit the changes to enable SMP support for MIPS.

I have put the diff here for review:
http://people.freebsd.org/~neel/mips_smp_patch/diff.txt

The mp_machdep.c file has changed a lot so it makes sense to read
these files separately:
http://people.freebsd.org/~neel/mips_smp_patch/mp_machdep.c
http://people.freebsd.org/~neel/mips_smp_patch/mpboot.S

Also, developers will be interested in the hooks that will be required
from the platform code. The APIs are documented here:
http://people.freebsd.org/~neel/mips_smp_patch/hwfunc.h

Please review.

best
Neel