net: bridge: mcast: toggle also host vlan state in br_multicast_toggle_vlan

When changing vlan mcast state by br_multicast_toggle_vlan it iterates
over all ports and enables/disables the port mcast ctx based on the new
state, but I forgot to update the host vlan (bridge master vlan entry)
with the new state so it will be left out. Also that function is not
used outside of br_multicast.c, so make it static.

Fixes: f4b7002a

 ("net: bridge: add vlan mcast snooping knob")
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>