drm/i915: Disable VRR during seamless M/N changes

drm/i915: Disable VRR during seamless M/N changes

Make life less confusing by making sure VRR is disabled whenever
we do any drastic changes to the display timings, such as seamless
M/N changes.

Cc: Manasi Navare <navaremanasi@chromium.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230901130440.2085-10-ville.syrjala@linux.intel.com
Reviewed-by: Manasi Navare <navaremanasi@chromium.org>
Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>