greybus: lights: remove has_flash on failure

If register to v4l2 fails just mark the light as not having flash so in
release we do not try to unregister.
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/light.c

@@ -1004,8 +1004,10 @@ static int gb_lights_light_register(struct gb_light *light)
 
 	if (light->has_flash) {
 		ret = gb_lights_light_v4l2_register(light);
-		if (ret < 0)
+		if (ret < 0) {
+			light->has_flash = false;
 			return ret;
+		}
 	}
 
 	return 0;