[PATCH] handle SLOB with sparsemen

This is to disallow to make SLOB with SMP or SPARSEMEM.  This avoids latent
troubles of SLOB with SLAB_DESTROY_BY_RCU.  And fix compile error.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>