[PATCH] powerpc: sched fixups

- Re-add a hunk lost during merge: ppc64 is missing the hunk that disables
  preempt on the secondary CPUs before they call cpu_idle().

- ppc's cpu_idle() had the need_resched() test wrong.

Cc: Nick Piggin <nickpiggin@yahoo.com.au>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>