net/mlx4_core: Add firmware commands to support device managed flow steering

Add support for firmware commands to attach/detach a new device managed
steering mode. Such network steering rules allow the user to provide an
L2/L3/L4 flow specification to the firmware and have the device to steer
traffic that matches that specification to the provided QP.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>