net: mdio-mux: bcm-iproc: call mdiobus_free() in error path

If an error is encountered in mdio_mux_init(), the error path will call
mdiobus_free().  Since mdiobus_register() has been called prior to
mdio_mux_init(), the bus->state will not be MDIOBUS_UNREGISTERED.  This
causes a BUG_ON() in mdiobus_free().  To correct this issue, add an
error path for mdio_mux_init() which calls mdiobus_unregister() prior to
mdiobus_free().

Signed-off-by: Jon Mason <jon.mason@broadcom.com>
Fixes: 98bc865a1ec8 ("net: mdio-mux: Add MDIO mux driver for iProc SoCs")
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mdio-mux-bcm-iproc.c

@@ -203,11 +203,14 @@ static int mdio_mux_iproc_probe(struct platform_device *pdev)
 			   &md->mux_handle, md, md->mii_bus);
 	if (rc) {
 		dev_info(md->dev, "mdiomux initialization failed\n");
-		goto out;
+		goto out_register;
 	}
 
 	dev_info(md->dev, "iProc mdiomux registered\n");
 	return 0;
+
+out_register:
+	mdiobus_unregister(bus);
 out:
 	mdiobus_free(bus);
 	return rc;