HID: wacom: Unregister sysfs attributes on remove

HID devices can be hotplugged so we should unregister all sysfs attributes when
removing a driver. Otherwise, manually unloading the wacom-driver will not
remove the sysfs attributes. Only when the device is disconnected, they are
removed, eventually.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-wacom.c

@@ -423,6 +423,7 @@ static void wacom_remove(struct hid_device *hdev)
 #ifdef CONFIG_HID_WACOM_POWER_SUPPLY
 	struct wacom_data *wdata = hid_get_drvdata(hdev);
 #endif
+	device_remove_file(&hdev->dev, &dev_attr_speed);
 	hid_hw_stop(hdev);
 
 #ifdef CONFIG_HID_WACOM_POWER_SUPPLY