net/mlx4_en: Fix ethtool rules leftovers after module unloaded

As part of the driver unload flow, all steering rules must be deleted,
make sure to remove the rules that were set through ethtool.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>