net/mlx5: Enable count action for rules with allow action

Enable the creation of rules with allow and count actions.
This enables using counters on egress flow tables.

Signed-off-by: Michael Guralnik <michaelgur@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>