drm/rockchip/rk628: max input resolution is 4k yuv420

Change-Id: I154b72b9ce3e975e62e9f107346eb57451dbb76d
Signed-off-by: Sandy Huang <hjc@rock-chips.com>

Author: sandy-huang

drivers/gpu/drm/rockchip/rk628/rk628_gvi.c

@@ -312,7 +312,8 @@ static int rk628_gvi_connector_get_modes(struct drm_connector *connector)
 	info->edid_hdmi_dc_modes = 0;
 	info->hdmi.y420_dc_modes = 0;
 	info->color_formats = 0;
-	info->max_tmds_clock = 600000;
+	info->max_tmds_clock = 300000;
+	connector->ycbcr_420_allowed = true;
 
 	num_modes += rk628_scaler_add_src_mode(gvi->parent, connector);