mdio_bus: implement devm_mdiobus_alloc/devm_mdiobus_free

Add a resource managed devm_mdiobus_alloc[_size]()/devm_mdiobus_free()
to automatically clean up MDIO bus alocations made by MDIO drivers,
thus leading to simplified MDIO drivers code.

Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-and-tested-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 51d15f6..864ddaf 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -198,6 +198,13 @@
 int mdiobus_register(struct mii_bus *bus);
 void mdiobus_unregister(struct mii_bus *bus);
 void mdiobus_free(struct mii_bus *bus);
+struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv);
+static inline struct mii_bus *devm_mdiobus_alloc(struct device *dev)
+{
+	return devm_mdiobus_alloc_size(dev, 0);
+}
+
+void devm_mdiobus_free(struct device *dev, struct mii_bus *bus);
 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr);
 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum);
 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val);