From: Mikael Pettersson <mikpe@csd.uu.se>

This patch fixes two p->thread_info->cpu occurrences in kernel/sched.c to
use the task_cpu(p) macro instead, which is optimised on UP.  Although one
of the occurrences is under #ifdef CONFIG_SMP, it's bad style to use the
raw non-optimisable form in non-arch code.