selftests: net: bridge: igmp: check for specific udp ip protocol

We have to specifically check for udp protocol in addition to the mac
address because in IGMPv3 tests group-specific queries will use the same
mac address.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/forwarding/bridge_igmp.sh

@@ -93,7 +93,7 @@ mcast_packet_test()
 	# was received by it or not.
 	tc qdisc add dev $host2_if ingress
 	tc filter add dev $host2_if ingress protocol ip pref 1 handle 101 \
-		flower dst_mac $mac action drop
+		flower ip_proto udp dst_mac $mac action drop
 
 	$MZ $host1_if -c 1 -p 64 -b $mac -A $src_ip -B $ip -t udp "dp=4096,sp=2048" -q
 	sleep 1