ACPI / video: Dummy acpi_video_register should return error code

The inline acpi_video_register stub simply allows compilation on systems
with CONFIG_ACPI_VIDEO disabled. the dummy acpi_video_register does not
register an acpi_bus_driver at all. The inline acpi_video_register should
return to indicate lack of support when attempting to register an
acpi_bus_driver on such a system with CONFIG_ACPI_VIDEO disabled.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/video.h

@@ -54,7 +54,7 @@ extern int acpi_video_get_levels(struct acpi_device *device,
 				 struct acpi_video_device_brightness **dev_br,
 				 int *pmax_level);
 #else
-static inline int acpi_video_register(void) { return 0; }
+static inline int acpi_video_register(void) { return -ENODEV; }
 static inline void acpi_video_unregister(void) { return; }
 static inline int acpi_video_get_edid(struct acpi_device *device, int type,
 				      int device_id, void **edid)