sched: Reduce some allocation pressure

Since we now allocate SD_LV_MAX * nr_cpu_ids sched_domain/sched_group
structures when rebuilding the scheduler toplogy it might make sense
to shrink that depending on the CONFIG_ options.

This is only needed until we get rid of SD_LV_* alltogether and
provide a full dynamic topology interface.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.406226449@chello.nl


Signed-off-by: Ingo Molnar <mingo@elte.hu>