phy: fix phy address bug

PHYID returns 0xffff and not 0xffffffff when not found and in some
case(at91sam9263) 0x0. Maybe this patch could be useful.
Signed-off-by: NGiulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/phy/phy_device.c

@@ -227,8 +227,8 @@ struct phy_device * get_phy_device(struct mii_bus *bus, int addr)
 	if (r)
 		return ERR_PTR(r);
 
-	/* If the phy_id is all Fs, there is no device there */
-	if (0xffffffff == phy_id)
+	/* If the phy_id is all Fs or all 0s, there is no device there */
+	if ((0xffff == phy_id) || (0x00 == phy_id))
 		return NULL;
 
 	dev = phy_device_create(bus, addr, phy_id);