drm/i915: Introduce intel_vrr_{vmin,vmax}_vtotal()

On ICL/TGL vmin/vmax/flipline won't actually match the
vtotal values (currently they do, but that is wrong and
needs to be fixed). Add a few helpers that will compute the
actual vtotal values for us.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241210211007.5976-5-ville.syrjala@linux.intel.com


Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>