IB/mlx4: Check for egress flow steering

ConnectX3 doesn't support egress flow steering. Return an EOPNOTSUPP
error when such a flow is being created.

Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Reviewed-by: Aviad Yehezkel <aviadye@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>