net/mlx5e: Support l3/l4 flow type specs in ethtool flow steering

Add support to add flow steering rules with ethtool
of L3/L4 flow types (ip4/tcp4/udp4).
Those rules will be in higher priority than l2 flow rules, in order
to prefer more specific rules.

Mask is not supported for l3/l4 flow types.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>