mm/slab_common.c: initialize kmem_cache pointer to NULL

The assignment to NULL within the error condition was written in a 2014
patch to suppress a compiler warning.  However it would be cleaner to just
initialize the kmem_cache to NULL and just return it in case of an error
condition.

Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
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/slab_common.c

@@ -384,7 +384,7 @@ struct kmem_cache *
 kmem_cache_create(const char *name, size_t size, size_t align,
 		  unsigned long flags, void (*ctor)(void *))
 {
-	struct kmem_cache *s;
+	struct kmem_cache *s = NULL;
 	const char *cache_name;
 	int err;
 
@@ -396,7 +396,6 @@ kmem_cache_create(const char *name, size_t size, size_t align,
 
 	err = kmem_cache_sanity_check(name, size);
 	if (err) {
-		s = NULL;	/* suppress uninit var warning */
 		goto out_unlock;
 	}