net: dsa: ocelot: seville: utilize of_mdiobus_register

Switch seville to use of_mdiobus_register(bus, NULL) instead of just
mdiobus_register. This code is about to be pulled into a separate module
that can optionally define ports by the device_node.
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/ocelot/seville_vsc9953.c

@@ -10,6 +10,7 @@
 #include <linux/pcs-lynx.h>
 #include <linux/dsa/ocelot.h>
 #include <linux/iopoll.h>
+#include <linux/of_mdio.h>
 #include "felix.h"
 
 #define MSCC_MIIM_CMD_OPR_WRITE			BIT(1)
@@ -1112,7 +1113,7 @@ static int vsc9953_mdio_bus_alloc(struct ocelot *ocelot)
 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-imdio", dev_name(dev));
 
 	/* Needed in order to initialize the bus mutex lock */
-	rc = mdiobus_register(bus);
+	rc = of_mdiobus_register(bus, NULL);
 	if (rc < 0) {
 		dev_err(dev, "failed to register MDIO bus\n");
 		return rc;