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>
diff --git a/drivers/hid/hid-wacom.c b/drivers/hid/hid-wacom.c
index f66a597..a597039 100644
--- a/drivers/hid/hid-wacom.c
+++ b/drivers/hid/hid-wacom.c
@@ -423,6 +423,7 @@
 #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