drm/i915: Use complete address space in true PPGTT

True PPGTT is capable of having a full address space, even if the system
has less allocated memory.

Note that aliasing PPGTT always aliases the GGTT and thus should remain
of the same size.
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -1030,11 +1030,9 @@ static int gen8_aliasing_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
 
 static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
 {
-	struct drm_device *dev = ppgtt->base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
 
-	ret = gen8_ppgtt_init_common(ppgtt, dev_priv->gtt.base.total);
+	ret = gen8_ppgtt_init_common(ppgtt, (1ULL << 32));
 	if (ret)
 		return ret;