SLUB: after object padding only needed for Redzoning

If no redzoning is selected then we do not need padding before the next
object.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>