drm/i915/vrr: Use optimized guardband whenever VRR TG is active

drm/i915/vrr: Use optimized guardband whenever VRR TG is active

Currently the guardband is optimized only for platforms where the
VRR timing generator is always ON.

Extend the usage of optimized guardband to all VRR supporting platforms.

v2: Drop check for `crtc_state->vrr.enable` and just return true
    unconditionally from intel_vrr_use_optimized_guardband(). (Ville)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20251017123504.2247954-6-ankit.k.nautiyal@intel.com