HID: wacom: power_supply: provide the actual model_name

Instead of displaying a generic "tablet", now g-c-c shows a pretty
"Wacom Intuos Pro S (WL)".

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.h b/drivers/hid/wacom.h
index 26a8a05..b4800ea 100644
--- a/drivers/hid/wacom.h
+++ b/drivers/hid/wacom.h
@@ -134,6 +134,7 @@
 };
 
 struct wacom_battery {
+	struct wacom *wacom;
 	struct power_supply_desc bat_desc;
 	struct power_supply *battery;
 	char bat_name[WACOM_NAME_MAX];