drivers: net: ethernet: cpsw: add multicast address to ALE table

Adding multicast address to ALE table via netdev ops to subscribe, transmit
or receive multicast frames to and from the network

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>