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>