USB: trancevibrator: convert to use dev_groups

USB drivers now support the ability for the driver core to handle the
creation and removal of device-specific sysfs files in a race-free
manner. Take advantage of that by converting the driver to use this by
moving the sysfs attributes into a group and assigning the dev_groups
pointer to it.

Cc: Ding Xiang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/misc/trancevibrator.c

···
 	}
 	return count;
 }
-
 static DEVICE_ATTR_RW(speed);
+
+static struct attribute *tv_attrs[] = {
+	&dev_attr_speed.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(tv);
 
 static int tv_probe(struct usb_interface *interface,
 		    const struct usb_device_id *id)
···
 
 	dev->udev = usb_get_dev(udev);
 	usb_set_intfdata(interface, dev);
-	retval = device_create_file(&interface->dev, &dev_attr_speed);
-	if (retval)
-		goto error_create_file;
 
 	return 0;
 
-error_create_file:
-	usb_put_dev(udev);
-	usb_set_intfdata(interface, NULL);
 error:
 	kfree(dev);
 	return retval;
···
 	struct trancevibrator *dev;
 
 	dev = usb_get_intfdata (interface);
-	device_remove_file(&interface->dev, &dev_attr_speed);
 	usb_set_intfdata(interface, NULL);
 	usb_put_dev(dev->udev);
 	kfree(dev);
···
 	.probe =	tv_probe,
 	.disconnect =	tv_disconnect,
 	.id_table =	id_table,
+	.dev_groups =	tv_groups,
 };
 
 module_usb_driver(tv_driver);