drm/i915/skl: Support the advertized index format

We advertize C8 in the primary plane formats didn't have the
corresponding code to set PLANE_CTL accordingly.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 file changed