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>
diff --git a/drivers/net/phy/bcm87xx.c b/drivers/net/phy/bcm87xx.c
index 71b491c..e536e30 100644
--- a/drivers/net/phy/bcm87xx.c
+++ b/drivers/net/phy/bcm87xx.c
@@ -40,10 +40,10 @@
 	const __be32 *paddr_end;
 	int len, ret;
 
-	if (!phydev->dev.of_node)
+	if (!phydev->mdio.dev.of_node)
 		return 0;
 
-	paddr = of_get_property(phydev->dev.of_node,
+	paddr = of_get_property(phydev->mdio.dev.of_node,
 				"broadcom,c45-reg-init", &len);
 	if (!paddr)
 		return 0;