drm/i915/vrr: Generate VRR "safe window" for DSB

drm/i915/vrr: Generate VRR "safe window" for DSB

Looks like TRANS_CHICKEN bit 31 means something totally different
depending on the platform:
TGL: generate VRR "safe window" for DSB
ADL/DG2: make TRANS_SET_CONTEXT_LATENCY effective with VRR

So far we've only set this on ADL/DG2, but when using DSB+VRR
we also need to set it on TGL.

And a quick test on MTL says it doesn't need this bit for either
of those purposes, even though it's still documented as valid
in bspec.

Cc: stable@vger.kernel.org
Fixes: 34d8311f4a1c ("drm/i915/dsb: Re-instate DSB for LUT updates")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9927
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306040806.21697-2-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>