net: bridge: vlan: add support for mcast querier global option

Add support to change and retrieve global vlan multicast querier state.
We just need to pass multicast context to br_multicast_set_querier
instead of bridge device and the rest of the logic remains the same.

Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>