net/mlx4_en: Manage hash of MAC addresses per port

As a preparation step for supporting multiple unicast addresses, store MAC addresses in hash table.
Remove the radix tree for MAC addresses per QP, as it's not in use.

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>