drm/i915: Make all clock checks non-fuzzy

Now that we backfeed the actual DPLL frequency into the
compute crtc state all our clocks should come out exact.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907091057.11572-11-ville.syrjala@linux.intel.com