drm/i915: Generalize PPGTT init

Rearrange the initialization code to try to special case the aliasing
PPGTT less, and provide usable interfaces for the general case later.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 file changed