[IPV6]: Fix per-socket multicast filtering in sk_reuse case

per-socket multicast filters were not being applied to all sockets
in the case of an exact-match bound address, due to an over-exuberant
"return" in the look-up code. Fix below. IPv4 does not have this problem.

Thanks to Hoerdt Mickael for reporting the bug.
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/udp.c

@@ -405,8 +405,7 @@ static struct sock *udp_v6_mcast_next(struct sock *sk,
 				continue;
 
 			if (!ipv6_addr_any(&np->rcv_saddr)) {
-				if (ipv6_addr_equal(&np->rcv_saddr, loc_addr))
-					return s;
+				if (!ipv6_addr_equal(&np->rcv_saddr, loc_addr))
 					continue;
 			}
 			if(!inet6_mc_check(s, loc_addr, rmt_addr))