HID: wacom: cleanup input devices

Just some cleaning up when the input devices are unregistered.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 5cb8528..9a41035 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -1357,6 +1357,9 @@
 	wacom->wacom_wac.pen_input = NULL;
 	wacom->wacom_wac.touch_input = NULL;
 	wacom->wacom_wac.pad_input = NULL;
+	wacom->wacom_wac.pen_registered = false;
+	wacom->wacom_wac.touch_registered = false;
+	wacom->wacom_wac.pad_registered = false;
 	wacom_destroy_leds(wacom);
 }