drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver

On the Amlogic SoCs, the DW-HDMI HW support is here but the DW-HDMI CEC signal
is not connected to a physical pin, leading to confusion when the dw-hdmi cec
controller can't communicate on the bus.

Disable it to avoid exposing a non-functinal bus.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20210416092737.1971876-3-narmstrong@baylibre.com

drivers/gpu/drm/meson/meson_dw_hdmi.c

@@ -1103,6 +1103,7 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 	dw_plat_data->phy_data = meson_dw_hdmi;
 	dw_plat_data->input_bus_encoding = V4L2_YCBCR_ENC_709;
 	dw_plat_data->ycbcr_420_allowed = true;
+	dw_plat_data->disable_cec = true;
 
 	if (dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-gxl-dw-hdmi") ||
 	    dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-gxm-dw-hdmi") ||