[bug report] net: arc_emac: Make use of the helper function dev_err_probe()

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hello Cai Huoqing,

The patch 95b5fc03c189: "net: arc_emac: Make use of the helper
function dev_err_probe()" from Sep 15, 2021, leads to the following
Smatch static checker warning:

	drivers/net/ethernet/arc/emac_mdio.c:170 arc_mdio_probe()
	error: dereferencing freed memory 'bus'

drivers/net/ethernet/arc/emac_mdio.c
    164         snprintf(bus->id, MII_BUS_ID_SIZE, "%s", bus->name);
    165 
    166         error = of_mdiobus_register(bus, priv->dev->of_node);
    167         if (error) {
    168                 mdiobus_free(bus);
                                     ^^^
Freed

    169                 return dev_err_probe(priv->dev, error,
--> 170                                      "cannot register MDIO bus %s\n", bus->name);
                                                                              ^^^^^
Use after free.

    171         }
    172 
    173         return 0;
    174 }

regards,
dan carpenter