drm/i915/dp: Rework HDMI DFP TMDS clock handling

Rework the HDMI DFP TMDS clock checks to also check at 8bpc.
Previously we only checked the deep color cases. But I suppose
a sink could potentially declare "4:2:0 also" modes that only
actually fit within its own limits when using 4:2:0. Even if
that is too nuts to be real there is no real harm in running
through the full checks for everything.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220322120015.28074-9-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>