A partitioned ppc64 machine can have a boot cpuid anywhere from 0 to 31.
With the non linear cpu changes in 2.5.24 we must set up the initial task
to start on the boot cpu. (since it isnt always 0 now)

With this patch I am able to boot on cpus other than 0. I also tested
discontiguous cpuids. So the non linear cpu stuff checks out OK.