drm/i915: Move the TMDS clock division into intel_hdmi_mode_clock_valid()

drm/i915: Move the TMDS clock division into intel_hdmi_mode_clock_valid()

Now that we have to tell intel_hdmi_mode_clock_valid() whether
we're asking about 4:4:4 or 4:2:0 output it can take care of
the dotclock->TMDS clock conversion.

Cc: Werner Sembach <wse@tuxedocomputers.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210511160532.21446-6-ville.syrjala@linux.intel.com
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>