drm/bridge: dw-hdmi: fix AVI frame colorimetry

CTA-861-F explicitly states that for RGB colorspace colorimetry should
be set to "none". Fix that.
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Fixes: def23aa7 ("drm: bridge: dw-hdmi: Switch to V4L bus format and encodings")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200304232512.51616-2-jernej.skrabec@siol.net

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

@@ -1624,6 +1624,7 @@ static void hdmi_config_AVI(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 		frame.colorspace = HDMI_COLORSPACE_RGB;
 
 	/* Set up colorimetry */
+	if (!hdmi_bus_fmt_is_rgb(hdmi->hdmi_data.enc_out_bus_format)) {
 		switch (hdmi->hdmi_data.enc_out_encoding) {
 		case V4L2_YCBCR_ENC_601:
 			if (hdmi->hdmi_data.enc_in_encoding == V4L2_YCBCR_ENC_XV601)
@@ -1647,6 +1648,11 @@ static void hdmi_config_AVI(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 					HDMI_EXTENDED_COLORIMETRY_XV_YCC_601;
 			break;
 		}
+	} else {
+		frame.colorimetry = HDMI_COLORIMETRY_NONE;
+		frame.extended_colorimetry =
+			HDMI_EXTENDED_COLORIMETRY_XV_YCC_601;
+	}
 
 	frame.scan_mode = HDMI_SCAN_MODE_NONE;