video: always update the brightness when poking "brightness"

always update props.brightness no matter the backlight is changed
via procfs, hotkeys or sysfs.
Sighed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/video.c

@@ -481,6 +481,7 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 	int status = AE_OK;
 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 	struct acpi_object_list args = { 1, &arg0 };
+	int state;
 
 
 	arg0.integer.value = level;
@@ -489,6 +490,10 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 		status = acpi_evaluate_object(device->dev->handle, "_BCM",
 					      &args, NULL);
 	device->brightness->curr = level;
+	for (state = 2; state < device->brightness->count; state++)
+		if (level == device->brightness->levels[state])
+			device->backlight->props.brightness = state - 2;
+
 	return status;
 }