[PATCH] slab: extract cache_free_alien from __cache_free

Move alien object freeing to cache_free_alien() to reduce #ifdef clutter in
__cache_free().

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>