R#33747 DUT reboot when configured multiple IPTV network

setting the lookup method to group_ip_src_ip_vid, to avoid reboot
while using multiple IPTV network.

Testing done:
- by configuring multiple IPTV network, as tag on WAN and untagged on LAN.
- by configuring network as untagged on both WAN and LAN.
- by sending join and leave to upstream server on both the above scenarios.

Change-Id: I806363ccde7336548d2321c2f247f709de379245

mcastmngr/files/broadcom/lib/mcast/broadcom.sh

@@ -235,7 +235,7 @@ configure_mcpd() {
 
 setup_mcast_mode() {
 	# set the mode at chip to allow both tagged and untagged multicast forwarding
-	bs /b/c iptv lookup_method=group_ip_src_ip
+	bs /b/c iptv lookup_method=group_ip_src_ip_vid
 }
 
 configure_mcast() {