net/mlx4_en: Add unicast MAC filtering

Implement and advertise unicast MAC filtering, such that setting macvlan
instance over mlx4_en interfaces will not require the networking core
to put mlx4_en devices in promiscuous mode.

If for some reason adding a unicast address filter fails e.g as of missing space in
the HW mac table, the device forces itself into promiscuous mode (and out of this
forced state when enough space is available).

Signed-off-by: Yan Burman <yanb@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>