bridge: memorize and export selected IGMP/MLD querier port

Adding bridge support to the batman-adv multicast optimization requires
batman-adv knowing about the existence of bridged-in IGMP/MLD queriers
to be able to reliably serve any multicast listener behind this same
bridge.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/linux/if_bridge.h
Simple merge

diff --cc net/bridge/br_multicast.c
Simple merge

diff --cc net/bridge/br_private.h
Simple merge