HID: wacom: Correct power_supply type

POWER_SUPPLY_TYPE_USB seems to only ever be used by USB ports that are
used to charge the machine itself (so a "system" scope), like the
single USB port on a phone, rather than devices.

The wacom_sys driver is the only driver that sets its device battery as
being a USB type, which doesn't seem correct based on its usage, so
switch it to be a battery type like all the other USB-connected devices.
Signed-off-by: Bastien Nocera <hadess@hadess.net>
Acked-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/wacom_sys.c

@@ -1777,7 +1777,7 @@ static int __wacom_initialize_battery(struct wacom *wacom,
 	bat_desc->get_property = wacom_battery_get_property;
 	sprintf(battery->bat_name, "wacom_battery_%ld", n);
 	bat_desc->name = battery->bat_name;
-	bat_desc->type = POWER_SUPPLY_TYPE_USB;
+	bat_desc->type = POWER_SUPPLY_TYPE_BATTERY;
 	bat_desc->use_for_apm = 0;
 
 	ps_bat = devm_power_supply_register(dev, bat_desc, &psy_cfg);