thermal/core: Make cooling device state change private

The change of the cooling device state should be used by the governor
or at least by the core code, not by the drivers themselves.

Remove the API usage and move the function declaration to the internal
headers.

Signed-off-by: Daniel Lezcano <[e-mail]>
Acked-by: Guenter Roeck <[e-mail]>
Acked-by: Zhang Rui <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/hwmon/pwm-fan.c

···
 			return ret;
 		}
 		ctx->cdev = cdev;
-		thermal_cdev_update(cdev);
 	}
 
 	return 0;

drivers/thermal/khadas_mcu_fan.c

···
 		return ret;
 	}
 	ctx->cdev = cdev;
-	thermal_cdev_update(cdev);
 
 	return 0;
 }

drivers/thermal/thermal_core.h

···
 		cdev->ops->power2state;
 }
 
+void thermal_cdev_update(struct thermal_cooling_device *);
+
 /**
  * struct thermal_trip - representation of a point in temperature domain
  * @np: pointer to struct device_node that this trip point was created from

include/linux/thermal.h

···
 int thermal_zone_get_slope(struct thermal_zone_device *tz);
 int thermal_zone_get_offset(struct thermal_zone_device *tz);
 
-void thermal_cdev_update(struct thermal_cooling_device *);
 void thermal_notify_framework(struct thermal_zone_device *, int);
 int thermal_zone_device_enable(struct thermal_zone_device *tz);
 int thermal_zone_device_disable(struct thermal_zone_device *tz);
···
 		struct thermal_zone_device *tz)
 { return -ENODEV; }
 
-static inline void thermal_cdev_update(struct thermal_cooling_device *cdev)
-{ }
 static inline void thermal_notify_framework(struct thermal_zone_device *tz,
 	int trip)
 { }