Hi Andrew

Current sizeof(percpu_data) is NR_CPUS*sizeof(void *)

This trivial patch makes percpu_data real size depends on 
highest_possible_processor_id() instead of NR_CPUS

percpu_data allocations are not performance critical, we can spend few CPU 
cycles and save some ram.

This patch should replace remove-unused-blkp-field-in-percpu_data.patch in mm tree

Thank you

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>