samsung-laptop: set backlight type

Cherry-picked from drivers/staging/samsung-laptop/samsung-laptop.c

Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/samsung-laptop.c

@@ -781,6 +781,7 @@ static int __init samsung_init(void)
 
 	/* create a backlight device to talk to this one */
 	memset(&props, 0, sizeof(struct backlight_properties));
+	props.type = BACKLIGHT_PLATFORM;
 	props.max_brightness = sabi_config->max_brightness;
 	backlight_device = backlight_device_register("samsung", &sdev->dev,
 						     NULL, &backlight_ops,