net: dsa: call teardown method on probe failure

Since teardown is supposed to undo the effects of the setup method, it
should be called in the error path for dsa_switch_setup, not just in
dsa_switch_teardown.

Fixes: 5e3f847a02aa ("net: dsa: Add teardown callback for drivers")
Signed-off-by: Vladimir Oltean <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/dsa/dsa2.c

···
 		ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
 		if (!ds->slave_mii_bus) {
 			err = -ENOMEM;
-			goto unregister_notifier;
+			goto teardown;
 		}
 
 		dsa_slave_mii_bus_init(ds);
 
 		err = mdiobus_register(ds->slave_mii_bus);
 		if (err < 0)
-			goto unregister_notifier;
+			goto teardown;
 	}
 
 	ds->setup = true;
 
 	return 0;
 
+teardown:
+	if (ds->ops->teardown)
+		ds->ops->teardown(ds);
 unregister_notifier:
 	dsa_switch_unregister_notifier(ds);
 unregister_devlink_ports: