arcnet: com20020-pci: set dev_port to the subdevice index

This patch sets the dev_port according to the index of
the card. This can be used by udev to name the ports
in userspace.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

drivers/net/arcnet/com20020-pci.c

@@ -96,6 +96,7 @@ static int com20020pci_probe(struct pci_dev *pdev,
 			ret = -ENOMEM;
 			goto out_port;
 		}
+		dev->dev_port = i;
 
 		dev->netdev_ops = &com20020_netdev_ops;