kernel/cred.c: use kmem_cache_free

Free memory allocated using kmem_cache_zalloc using kmem_cache_free rather
than kfree.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,E,c;
@@

 x = \(kmem_cache_alloc\|kmem_cache_zalloc\|kmem_cache_alloc_node\)(c,...)
 ... when != x = E
     when != &x
?-kfree(x)
+kmem_cache_free(c,x)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Steve Dickson <steved@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>

kernel/cred.c

@@ -224,7 +224,7 @@ struct cred *cred_alloc_blank(void)
 #ifdef CONFIG_KEYS
 	new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL);
 	if (!new->tgcred) {
-		kfree(new);
+		kmem_cache_free(cred_jar, new);
 		return NULL;
 	}
 	atomic_set(&new->tgcred->usage, 1);