drm/bridge: display-connector: allow YCbCr 420 for HDMI and DP

Allow YCbCr 420 output for HDMI and DisplayPort connectors. Other
bridges in the chain still might limit YCbCr 420 support on the
corresponding connector.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20241019-bridge-yuv420-v1-3-d74efac9e4e6@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>