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 <[e-mail]>
Acked-by: David Howells <[e-mail]>
Cc: James Morris <[e-mail]>
Cc: Steve Dickson <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: James Morris <[e-mail]>

kernel/cred.c

···
 #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);