netfilter: use kfree_skb() not kfree()

This was should be a kfree_skb() here to free the sk_buff pointer.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/netfilter/ebt_ulog.c

@@ -156,7 +156,7 @@ static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
 	nlh = nlmsg_put(ub->skb, 0, ub->qlen, 0,
 			size - NLMSG_ALIGN(sizeof(*nlh)), 0);
 	if (!nlh) {
-		kfree(ub->skb);
+		kfree_skb(ub->skb);
 		ub->skb = NULL;
 		goto unlock;
 	}