This patch fix error with CONFIG_TCP_MD5SIG disabled.
Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
 {
        struct tcphdr *th = tcp_hdr(skb);
        u32 seq = 0, ack_seq = 0;
-#ifdef CONFIG_TCP_MD5SIG
-       struct tcp_md5sig_key *key;
-#endif
+       struct tcp_md5sig_key *key = NULL;
 
        if (th->rst)
                return;
 #ifdef CONFIG_TCP_MD5SIG
        if (sk)
                key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr);
-       else
-               key = NULL;
 #endif
 
        if (th->ack)