USB: phy: twl6030: 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/20190806073235.25140-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/phy-twl6030-usb.c

@@ -196,6 +196,12 @@ static ssize_t vbus_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(vbus);
 
+static struct attribute *twl6030_attrs[] = {
+	&dev_attr_vbus.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(twl6030);
+
 static irqreturn_t twl6030_usb_irq(int irq, void *_twl)
 {
 	struct twl6030_usb *twl = _twl;
@@ -361,8 +367,6 @@ static int twl6030_usb_probe(struct platform_device *pdev)
 	}
 
 	platform_set_drvdata(pdev, twl);
-	if (device_create_file(&pdev->dev, &dev_attr_vbus))
-		dev_warn(&pdev->dev, "could not create sysfs file\n");
 
 	INIT_WORK(&twl->set_vbus_work, otg_set_vbus_work);
 	INIT_DELAYED_WORK(&twl->get_status_work, twl6030_status_work);
@@ -373,7 +377,6 @@ static int twl6030_usb_probe(struct platform_device *pdev)
 	if (status < 0) {
 		dev_err(&pdev->dev, "can't get IRQ %d, err %d\n",
 			twl->irq1, status);
-		device_remove_file(twl->dev, &dev_attr_vbus);
 		return status;
 	}
 
@@ -384,7 +387,6 @@ static int twl6030_usb_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "can't get IRQ %d, err %d\n",
 			twl->irq2, status);
 		free_irq(twl->irq1, twl);
-		device_remove_file(twl->dev, &dev_attr_vbus);
 		return status;
 	}
 
@@ -408,7 +410,6 @@ static int twl6030_usb_remove(struct platform_device *pdev)
 	free_irq(twl->irq1, twl);
 	free_irq(twl->irq2, twl);
 	regulator_put(twl->usb3v3);
-	device_remove_file(twl->dev, &dev_attr_vbus);
 	cancel_work_sync(&twl->set_vbus_work);
 
 	return 0;
@@ -426,6 +427,7 @@ static struct platform_driver twl6030_usb_driver = {
 	.driver		= {
 		.name	= "twl6030_usb",
 		.of_match_table = of_match_ptr(twl6030_usb_id_table),
+		.dev_groups = twl6030_groups,
 	},
 };