drm/connector: hdmi: Validate supported_formats matches ycbcr_420_allowed

Ensure HDMI connector initialization fails when the presence of
HDMI_COLORSPACE_YUV420 in the given supported_formats bitmask doesn't
match the value of drm_connector->ycbcr_420_allowed.

Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20241224-bridge-conn-fmt-prio-v4-3-a9ceb5671379@collabora.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Author: cristicc

drivers/gpu/drm/drm_connector.c

@@ -507,6 +507,9 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
 	if (!supported_formats || !(supported_formats & BIT(HDMI_COLORSPACE_RGB)))
 		return -EINVAL;
 
+	if (connector->ycbcr_420_allowed != !!(supported_formats & BIT(HDMI_COLORSPACE_YUV420)))
+		return -EINVAL;
+
 	if (!(max_bpc == 8 || max_bpc == 10 || max_bpc == 12))
 		return -EINVAL;