dax-device: Make remove callback return void

The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct dax_device_driver::remove()
return void, too. All users already unconditionally return 0, this commit
makes it obvious that returning an error code isn't intended.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-6-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index d2419e8..452e85a 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -178,12 +178,11 @@ static int dax_bus_remove(struct device *dev)
 {
 	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
 	struct dev_dax *dev_dax = to_dev_dax(dev);
-	int ret = 0;
 
 	if (dax_drv->remove)
-		ret = dax_drv->remove(dev_dax);
+		dax_drv->remove(dev_dax);
 
-	return ret;
+	return 0;
 }
 
 static struct bus_type dax_bus_type = {