netfilter: nfnetlink_queue: remove pointless conditional before kfree_skb()

Remove pointless conditional before kfree_skb().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink_queue_core.c

@@ -406,7 +406,6 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
 	return skb;
 
 nla_put_failure:
-	if (skb)
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 	return NULL;