thermal: Remove thermal_zone_device_update() stub

All users of the function depends on THERMAL, no stub is
needed. Remove it.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20200402142747.8307-9-daniel.lezcano@linaro.org

include/linux/thermal.h

@@ -426,9 +426,6 @@ static inline struct thermal_zone_device *thermal_zone_device_register(
 static inline void thermal_zone_device_unregister(
 	struct thermal_zone_device *tz)
 { }
-static inline void thermal_zone_device_update(struct thermal_zone_device *tz,
-					      enum thermal_notify_event event)
-{ }
 static inline struct thermal_cooling_device *
 thermal_cooling_device_register(char *type, void *devdata,
 	const struct thermal_cooling_device_ops *ops)