drm/i915: Make intel_fuzzy_clock_check() take in arbitrary clocks

We want to do fuzzy clock checks for other things besides
adjusted_mode.clock, so just pass two two clocks to compare
to intel_fuzzy_clock_check().

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>