drm/i915/dp: Duplicate native HDMI TMDS clock limit handling for DP HDMI DFPs

With native HDMI we allow the user to override the mode with
something that may not respect the downstream (sink,dual-mode adapter)
TMDS clock limits. Let's reuse the same logic for DP HDMI DFPs
so that behaviour is more or less uniform.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220322120015.28074-11-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>