drm/bridge: synopsys: dw-hdmi: Select formula1 for csc decimation

Formula3 and Formula2 for csc decimation will cause hdmi yuv422
display err.

Formula3:
The pixel color of left 0-14 columns and right 0-12 columns is
err.

Formula2:
The pixel color of left 0-2 columns is err.

Change-Id: I94fdd5fd962a24fde02dde1fe3ac10437ad117ad
Signed-off-by: Algea Cao <algea.cao@rock-chips.com>

Author: Algea Cao

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

@@ -1085,7 +1085,7 @@ static void hdmi_video_csc(struct dw_hdmi *hdmi)
 	if (is_color_space_interpolation(hdmi))
 		interpolation = HDMI_CSC_CFG_INTMODE_CHROMA_INT_FORMULA1;
 	else if (is_color_space_decimation(hdmi))
-		decimation = HDMI_CSC_CFG_DECMODE_CHROMA_INT_FORMULA3;
+		decimation = HDMI_CSC_CFG_DECMODE_CHROMA_INT_FORMULA1;
 
 	switch (hdmi_bus_fmt_color_depth(hdmi->hdmi_data.enc_out_bus_format)) {
 	case 8: