thermal: hwmon: EXPORT_SYMBOL_GPL for thermal hwmon sysfs

thermal_add_hwmon_sysfs()/thermal_remove_hwmon_sysfs() need
EXPORT_SYMBOL_GPL(). Otherwise we will have ERROR

>> ERROR: "thermal_remove_hwmon_sysfs" [drivers/thermal/rcar_thermal.ko] undefined!
>> ERROR: "thermal_add_hwmon_sysfs" [drivers/thermal/rcar_thermal.ko] undefined!
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

drivers/thermal/thermal_hwmon.c

@@ -232,6 +232,7 @@ int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 
 	return result;
 }
+EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 
 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 {
@@ -270,3 +271,4 @@ void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 	hwmon_device_unregister(hwmon->device);
 	kfree(hwmon);
 }
+EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);