slub: remove useless kmem_cache_debug() before remove_full()

When CONFIG_SLUB_DEBUG is not enabled, remove_full() is empty.
While CONFIG_SLUB_DEBUG is enabled, remove_full() can check
s->flags by itself. So kmem_cache_debug() is useless and
can be removed.

Link: http://lkml.kernel.org/r/1552577313-2830-1-git-send-email-liu.xiang6@zte.com.cnSigned-off-by: Liu Xiang <liu.xiang6@zte.com.cn>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -2903,8 +2903,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 	 * then add it.
 	 */
 	if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
-		if (kmem_cache_debug(s))
-			remove_full(s, n, page);
+		remove_full(s, n, page);
 		add_partial(n, page, DEACTIVATE_TO_TAIL);
 		stat(s, FREE_ADD_PARTIAL);
 	}