drm/panel: vtdr6130: fix unused ret in visionox_vtdr6130_bl_update_status

Fix the following warning:
panel-visionox-vtdr6130.c:249:12: warning: 'ret' is used uninitialized [-Wuninitialized]

Fixes: 9402cde9 ("drm/panel: vtdr6130: Use 16-bit brightness function")
Reported-by: Daniel Vetter <daniel@ffwll.ch>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230119-topic-sm8550-vtdr6130-fixup-v1-1-82c4fb008138@linaro.org

drivers/gpu/drm/panel/panel-visionox-vtdr6130.c

@@ -243,13 +243,8 @@ static int visionox_vtdr6130_bl_update_status(struct backlight_device *bl)
 {
 	struct mipi_dsi_device *dsi = bl_get_data(bl);
 	u16 brightness = backlight_get_brightness(bl);
-	int ret;
 
-	mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
-	if (ret < 0)
-		return ret;
-
-	return 0;
+	return mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
 }
 
 static const struct backlight_ops visionox_vtdr6130_bl_ops = {