net: bridge: Add/del switchdev object on host join/leave

When the host joins or leaves a multicast group, use switchdev to add
an object to the hardware to forward traffic for the group to the
host.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>