drm/i915: Extend the async flip VT-d w/a to skl/bxt

drm/i915: Extend the async flip VT-d w/a to skl/bxt

Looks like skl/bxt/derivatives also need the plane stride
stretch w/a when using async flips and VT-d is enabled, or
else we get corruption on screen. To my surprise this was
even documented in bspec, but only as a note on the
CHICHKEN_PIPESL register description rather than on the
w/a list.

So very much the same thing as on HSW/BDW, except the bits
moved yet again.

Cc: stable@vger.kernel.org
Cc: Karthik B S <karthik.b.s@intel.com>
Fixes: 55ea1cb178ef ("drm/i915: Enable async flips in i915")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930190943.17547-1-ville.syrjala@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>