of: mdio: Refactor of_get_phy_id()

With the introduction of fwnode_get_phy_id(), refactor of_get_phy_id()
to use fwnode equivalent.

Signed-off-by: Calvin Johnson <calvin.johnson@oss.nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Acked-by: Grant Likely <grant.likely@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/mdio/of_mdio.c

@@ -29,17 +29,7 @@ MODULE_LICENSE("GPL");
  * ethernet-phy-idAAAA.BBBB */
 static int of_get_phy_id(struct device_node *device, u32 *phy_id)
 {
-	struct property *prop;
-	const char *cp;
-	unsigned int upper, lower;
-
-	of_property_for_each_string(device, "compatible", prop, cp) {
-		if (sscanf(cp, "ethernet-phy-id%4x.%4x", &upper, &lower) == 2) {
-			*phy_id = ((upper & 0xFFFF) << 16) | (lower & 0xFFFF);
-			return 0;
-		}
-	}
-	return -EINVAL;
+	return fwnode_get_phy_id(of_fwnode_handle(device), phy_id);
 }
 
 static struct mii_timestamper *of_find_mii_timestamper(struct device_node *node)