net/mlx5e: Use IP version matching to classify IP traffic

This change adds the ability for flow steering to classify IPv4/6
packets with MPLS tag (Ethertype 0x8847 and 0x8848) as standard IP
packets and hit IPv4/6 classification steering rules.

Since IP packets with MPLS tag header have MPLS ethertype, they
missed the IPv4/6 ethertype rule and ended up hitting the default
filter forwarding all the packets to the same single RQ (No RSS).

Since our device is able to look past the MPLS tag and identify the
next protocol we introduce this solution which replaces ethertype
matching by the device's capability to perform IP version
identification and matching in order to distinguish between IPv4 and
IPv6.
Therefore, when driver is performing flow steering configuration on the
device it will use IP version matching in IP classified rules instead
of ethertype matching which will cause relevant MPLS tagged packets to
hit this rule as well.

If the device doesn't support IP version matching the driver will fall back
to use legacy ethertype matching in the steering as before.

Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>