powerpc/booke: Use the 'tlbilx' instruction on newer cores

Newer cores have the 'tlbilx' instruction, which doesn't broadcast over
CoreNet. This is significantly faster than walking the TLB to invalidate
the PID mappings. tlbilx with the arguments given takes 131 clock cycles to
complete, as opposed to 512 iterations through the loop plus tlbre/tlbwe at
each iteration.

MFC after: 3 weeks