udp_diag: Fix the !ipv6 case

Wrap the udp6 lookup into the proper ifdef-s.
Signed-off-by: NPavel Emelyanov <xemul@parallels.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/udp_diag.c

@@ -41,6 +41,7 @@ static int udp_dump_one(struct udp_table *tbl, struct sk_buff *in_skb,
 				req->id.idiag_src[0], req->id.idiag_sport,
 				req->id.idiag_dst[0], req->id.idiag_dport,
 				req->id.idiag_if, tbl);
+#if IS_ENABLED(CONFIG_IPV6)
 	else if (req->sdiag_family == AF_INET6)
 		sk = __udp6_lib_lookup(&init_net,
 				(struct in6_addr *)req->id.idiag_src,
@@ -48,6 +49,7 @@ static int udp_dump_one(struct udp_table *tbl, struct sk_buff *in_skb,
 				(struct in6_addr *)req->id.idiag_dst,
 				req->id.idiag_dport,
 				req->id.idiag_if, tbl);
+#endif
 	else
 		goto out_nosk;