USB: phy: mv-usb: convert platform driver to use dev_groups

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" any sysfs files.

Cc: Felipe Balbi <balbi@kernel.org>
Link: https://lore.kernel.org/r/20190805193636.25560-3-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/phy-mv-usb.c

@@ -641,12 +641,15 @@ static const struct attribute_group inputs_attr_group = {
 	.attrs = inputs_attrs,
 };
 
+static const struct attribute_group *mv_otg_groups[] = {
+	&inputs_attr_group,
+	NULL,
+};
+
 static int mv_otg_remove(struct platform_device *pdev)
 {
 	struct mv_otg *mvotg = platform_get_drvdata(pdev);
 
-	sysfs_remove_group(&mvotg->pdev->dev.kobj, &inputs_attr_group);
-
 	if (mvotg->qwork) {
 		flush_workqueue(mvotg->qwork);
 		destroy_workqueue(mvotg->qwork);
@@ -809,13 +812,6 @@ static int mv_otg_probe(struct platform_device *pdev)
 		goto err_disable_clk;
 	}
 
-	retval = sysfs_create_group(&pdev->dev.kobj, &inputs_attr_group);
-	if (retval < 0) {
-		dev_dbg(&pdev->dev,
-			"Can't register sysfs attr group: %d\n", retval);
-		goto err_remove_phy;
-	}
-
 	spin_lock_init(&mvotg->wq_lock);
 	if (spin_trylock(&mvotg->wq_lock)) {
 		mv_otg_run_state_machine(mvotg, 2 * HZ);
@@ -828,8 +824,6 @@ static int mv_otg_probe(struct platform_device *pdev)
 
 	return 0;
 
-err_remove_phy:
-	usb_remove_phy(&mvotg->phy);
 err_disable_clk:
 	mv_otg_disable_internal(mvotg);
 err_destroy_workqueue:
@@ -883,6 +877,7 @@ static struct platform_driver mv_otg_driver = {
 	.remove = mv_otg_remove,
 	.driver = {
 		   .name = driver_name,
+		   .dev_groups = mv_otg_groups,
 		   },
 #ifdef CONFIG_PM
 	.suspend = mv_otg_suspend,