cpmac: fallback to switch mode if no PHY chip found

If we were unable to detect a PHY on any of the MDIO bus id we tried instead of
bailing out with -ENODEV, assume the MAC is connected to a switch and use MDIO
bus 0. This unbreaks quite a lot of devices out there whose switch cannot be
detected.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/cpmac.c

@@ -1137,8 +1137,9 @@ static int __devinit cpmac_probe(struct platform_device *pdev)
 	}
 
 	if (phy_id == PHY_MAX_ADDR) {
-		dev_err(&pdev->dev, "no PHY present\n");
-		return -ENODEV;
+		dev_err(&pdev->dev, "no PHY present, falling back to switch on MDIO bus 0\n");
+		strncpy(mdio_bus_id, "0", MII_BUS_ID_SIZE); /* fixed phys bus */
+		phy_id = pdev->id;
 	}
 
 	dev = alloc_etherdev_mq(sizeof(*priv), CPMAC_QUEUES);