drm/i915/dp: Extract intel_dp_tmds_clock_valid()

We're currently duplicating the DFP min/max TMDS clock checks
in .mode_valid() and .compute_config(). Extract a helper suitable
for both use cases.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220322120015.28074-2-ville.syrjala@linux.intel.com


Reviewed-by: Uma Shankar <uma.shankar@intel.com>