We need this because ppgtt page directory entries need to be in the
global gtt pagetable.
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Reviewed-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>