slub: fix incorrect return type of get_any_partial()

Commit 497b66f2ecc97844493e6a147fd5a7e73f73f408 ('slub: return object pointer
from get_partial() / new_slab().') changed return type of some functions.
This updates missing part.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

mm/slub.c

@@ -1579,7 +1579,7 @@ static void *get_partial_node(struct kmem_cache *s,
 /*
  * Get a page from somewhere. Search in increasing NUMA distances.
  */
-static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags,
+static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
 		struct kmem_cache_cpu *c)
 {
 #ifdef CONFIG_NUMA