net/mlx4_en: Add steering rules after RSS creation

Changed the receive control flow in a way that steering
rules are added only when the RSS object is already in RTR/RTS mode.
Some optimization features, which are enabled by the device firmware,
require this condition in order to be effective.

Signed-off-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>