drm/mediatek: hdmi: Add optional limit on maximal HDMI mode clock

Some SoCs like the MT8167 have a hard limit on the maximal
supported HDMI TMDS clock, so add a configuration value to
filter out those modes.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>