net/mlx4_en: Cleanup MAC resources on module unload or port stop

Make sure we cleanup all MAC related resources (entries in the port MAC
table and steering rules) when stopping a port or when the driver is unloaded.

The leak was introduced by commit 07cb4b0a "net/mlx4_en: Manage hash of MAC
addresses per port".

Signed-off-by: Yan Burman <yanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>