drm/vc4: hdmi: Take the sink maximum TMDS clock into account

In the function that validates that the clock isn't too high, we've only
taken our controller limitations into account so far.

However, the sink can have a limit on the maximum TMDS clock it can deal
with too which is exposed through the EDID and the drm_display_info.

Make sure we check it.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>