drm/rockchip: vop: report error when check resource error

The user would be confused while facing a error commit without
any error report.
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
Reviewed-by: Sandy huang <sandy.huang@rock-chips.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1501494596-7090-1-git-send-email-mark.yao@rock-chips.com

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

@@ -675,8 +675,10 @@ static int vop_plane_atomic_check(struct drm_plane *plane,
 	 * Src.x1 can be odd when do clip, but yuv plane start point
 	 * need align with 2 pixel.
 	 */
-	if (is_yuv_support(fb->format->format) && ((state->src.x1 >> 16) % 2))
+	if (is_yuv_support(fb->format->format) && ((state->src.x1 >> 16) % 2)) {
+		DRM_ERROR("Invalid Source: Yuv format not support odd xpos\n");
 		return -EINVAL;
+	}
 
 	return 0;
 }