thermal: Use bool function return values of true/false not 1/0

Use the normal return values for bool functions

Signed-off-by: Joe Perches <[e-mail]>
Signed-off-by: Zhang Rui <[e-mail]>

drivers/thermal/thermal_core.h

···
 static inline bool of_thermal_is_trip_valid(struct thermal_zone_device *tz,
 					    int trip)
 {
-	return 0;
+	return false;
 }
 static inline const struct thermal_trip *
 of_thermal_get_trip_points(struct thermal_zone_device *tz)