For dual_emac mode, the driver needs to send on the individual
ports. We set the directional bits on each packet so the controller
knows where to send its.

From TI am335x Reference Manual:

14.3.2.10.2 Dual Mac Mode

- Packets from the host (port 0) to ports 1 and 2 should be directed.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>