net: fix build errors if ipv6 is disabled

CONFIG_IPV6=n is still a valid choice ;)

It appears we can remove dead code.

Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sunrpc/svcsock.c

@@ -291,12 +291,14 @@ static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
 				&inet_sk(sk)->inet_rcv_saddr,
 				inet_sk(sk)->inet_num);
 		break;
+#if IS_ENABLED(CONFIG_IPV6)
 	case PF_INET6:
 		len = snprintf(buf, remaining, "ipv6 %s %pI6 %d\n",
 				proto_name,
 				&sk->sk_v6_rcv_saddr,
 				inet_sk(sk)->inet_num);
 		break;
+#endif
 	default:
 		len = snprintf(buf, remaining, "*unknown-%d*\n",
 				sk->sk_family);