mlxsw: spectrum: Add an option to flood mc by mc_router_port

The decision whether to flood a multicast packet to a port dependent
on three flags: mc_disabled, mc_router_port, mc_flood.

If mc_disabled is on, the port will be flooded according to mc_flood,
otherwise, according to mc_router_port. To accomplish that, add those
flags into the mlxsw_sp_port struct and update the mc flood table
accordingly.

Update mc_router_port by switchdev attribute
SWITCHDEV_ATTR_ID_PORT_MC_ROUTER_PORT.

Signed-off-by: Nogah Frankel <nogahf@mellanox.com>
Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>