phy: Add an mdio_device structure

Not all devices attached to an MDIO bus are phys. So add an
mdio_device structure to represent the generic parts of an mdio
device, and place this structure into the phy_device.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/davinci_mdio.c

@@ -396,7 +396,7 @@ static int davinci_mdio_probe(struct platform_device *pdev)
 		phy = data->bus->phy_map[addr];
 		if (phy) {
 			dev_info(dev, "phy[%d]: device %s, driver %s\n",
-				 phy->addr, phydev_name(phy),
+				 phy->mdio.addr, phydev_name(phy),
 				 phy->drv ? phy->drv->name : "unknown");
 		}
 	}