ethdev: add represented port action to flow API

ethdev: add represented port action to flow API

For use in "transfer" flows. Supposed to send matching traffic to the
entity represented by the given ethdev, at embedded switch level.
Such an entity can be a network (via a network port), a guest
machine (via a VF) or another ethdev in the same application.

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Acked-by: Ori Kam <orika@nvidia.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>