net/mlx4_core: Add explicit error message when rule doesn't meet configuration

When a given flow steering rule is invalid in respect to the current
steering configuration, print the correct error message to the system log.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>