drm/i915: Correct PPGTT total size
drm/i915: Correct PPGTT total size

Our code allows have a PPGTT that is smaller than the maximum size for
GEN6-GEN7. Though I don't think this actually ever occurs, the code may
as well work properly and more importantly look correct by using the
variable size instead of the HW max.

Signed-off-by: Ben Widawsky <73675debcd8a436be48ec22211dcf44fe0df0a64@bwidawsk.net>
Reviewed-by: Chris Wilson <711c73f64afdce07b7e38039a96d2224209e9a6c@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs