[IPV6]: Sparse: Reuse previous delaration where appropriate.

| net/ipv6/ipv6_sockglue.c:162:16: warning: symbol 'net' shadows an earlier one
| net/ipv6/ipv6_sockglue.c:111:13: originally declared here
| net/ipv6/ipv6_sockglue.c:175:16: warning: symbol 'net' shadows an earlier one
| net/ipv6/ipv6_sockglue.c:111:13: originally declared here
| net/ipv6/ip6mr.c:1241:10: warning: symbol 'ret' shadows an earlier one
| net/ipv6/ip6mr.c:1163:6: originally declared here
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

net/ipv6/ip6mr.c

@@ -1238,7 +1238,7 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, int
 #ifdef CONFIG_IPV6_PIMSM_V2
 	case MRT6_PIM:
 	{
-		int v, ret;
+		int v;
 		if (get_user(v, (int __user *)optval))
 			return -EFAULT;
 		v = !!v;

net/ipv6/ipv6_sockglue.c

@@ -159,8 +159,6 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 
 			if (sk->sk_protocol == IPPROTO_TCP) {
 				struct inet_connection_sock *icsk = inet_csk(sk);
-				struct net *net = sock_net(sk);
-
 				local_bh_disable();
 				sock_prot_inuse_add(net, sk->sk_prot, -1);
 				sock_prot_inuse_add(net, &tcp_prot, 1);
@@ -172,7 +170,6 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 				tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
 			} else {
 				struct proto *prot = &udp_prot;
-				struct net *net = sock_net(sk);
 
 				if (sk->sk_protocol == IPPROTO_UDPLITE)
 					prot = &udplite_prot;