tcp: md5: hide unused variable

Changing from a memcpy to per-member comparison left the
size variable unused:

net/ipv4/tcp_ipv4.c: In function 'tcp_md5_do_lookup':
net/ipv4/tcp_ipv4.c:910:15: error: unused variable 'size' [-Werror=unused-variable]

This does not show up when CONFIG_IPV6 is enabled, but the
variable can be removed either way, along with the now unused
assignment.

Fixes: 6797318e ("tcp: md5: add an address prefix for key lookup")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_ipv4.c

@@ -907,7 +907,6 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_md5sig_key *key;
-	unsigned int size = sizeof(struct in_addr);
 	const struct tcp_md5sig_info *md5sig;
 	__be32 mask;
 	struct tcp_md5sig_key *best_match = NULL;
@@ -918,10 +917,7 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
 				       lockdep_sock_is_held(sk));
 	if (!md5sig)
 		return NULL;
-#if IS_ENABLED(CONFIG_IPV6)
-	if (family == AF_INET6)
-		size = sizeof(struct in6_addr);
-#endif
+
 	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
 		if (key->family != family)
 			continue;