net: miiphy: Introduce mdio_init()

Introduce mdio_init() split off from mdio_alloc(), which is used
to initialize already allocated struct mii_dev.

Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

common/miiphyutil.c

@@ -65,6 +65,14 @@ void miiphy_init(void)
 	current_mii = NULL;
 }
 
+void mdio_init(struct mii_dev *bus)
+{
+	memset(bus, 0, sizeof(*bus));
+
+	/* initialize mii_dev struct fields */
+	INIT_LIST_HEAD(&bus->link);
+}
+
 struct mii_dev *mdio_alloc(void)
 {
 	struct mii_dev *bus;
@@ -73,10 +81,7 @@ struct mii_dev *mdio_alloc(void)
 	if (!bus)
 		return bus;
 
-	memset(bus, 0, sizeof(*bus));
-
-	/* initalize mii_dev struct fields */
-	INIT_LIST_HEAD(&bus->link);
+	mdio_init(bus);
 
 	return bus;
 }

include/miiphy.h

@@ -44,6 +44,7 @@ struct phy_device *mdio_phydev_for_ethname(const char *devname);
 
 void miiphy_listdev(void);
 
+void mdio_init(struct mii_dev *bus);
 struct mii_dev *mdio_alloc(void);
 void mdio_free(struct mii_dev *bus);
 int mdio_register(struct mii_dev *bus);