net/mlx5: E-Switch, Introduce flow counter affinity

This dictates the device affinity for eswitch flow counters, set by the FW
according to the HW device capabilities.

Under "source eswitch" affinity, the counter should be allocated on the
device related to the source vport in the match. This covers both non
merged e-switch mode as well as old FW that does not advertise this cap.

Under "flow eswitch" affinity, the counter should be allocated on the
device where the eswitch rule is set.

Signed-off-by: Shahar Klein <shahark@mellanox.com>
Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>