video / backlight: remove the backlight_device_registered API

Since we will need the backlight_device_get_by_type API, we can use it
instead of the backlight_device_registered API whenever necessary so
remove the backlight_device_registered API.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/video_detect.c

@@ -358,7 +358,7 @@ enum acpi_backlight_type acpi_video_get_backlight_type(void)
 	if (!(video_caps & ACPI_VIDEO_BACKLIGHT))
 		return acpi_backlight_vendor;
 
-	if (acpi_osi_is_win8() && backlight_device_registered(BACKLIGHT_RAW))
+	if (acpi_osi_is_win8() && backlight_device_get_by_type(BACKLIGHT_RAW))
 		return acpi_backlight_native;
 
 	return acpi_backlight_video;

drivers/video/backlight/backlight.c

@@ -407,12 +407,6 @@ struct backlight_device *backlight_device_get_by_type(enum backlight_type type)
 }
 EXPORT_SYMBOL(backlight_device_get_by_type);
 
-bool backlight_device_registered(enum backlight_type type)
-{
-	return backlight_device_get_by_type(type) ? true : false;
-}
-EXPORT_SYMBOL(backlight_device_registered);
-
 /**
  * backlight_device_unregister - unregisters a backlight device object.
  * @bd: the backlight device object to be unregistered and freed.

include/linux/backlight.h

@@ -141,7 +141,6 @@ extern void devm_backlight_device_unregister(struct device *dev,
 					struct backlight_device *bd);
 extern void backlight_force_update(struct backlight_device *bd,
 				   enum backlight_update_reason reason);
-extern bool backlight_device_registered(enum backlight_type type);
 extern int backlight_register_notifier(struct notifier_block *nb);
 extern int backlight_unregister_notifier(struct notifier_block *nb);
 extern struct backlight_device *backlight_device_get_by_type(enum backlight_type type);