[NETFILTER]: Missing unlock in TCP connection tracking error path

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ip_conntrack_proto_tcp.c

@@ -349,6 +349,7 @@ static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
 	return 0;
 
 nfattr_failure:
+	read_unlock_bh(&tcp_lock);
 	return -1;
 }
 #endif