agp/intel: Remove confusion of stolen entries not stolen memory

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 3df2712..86b0e80 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1044,7 +1044,7 @@
 		pci_read_config_byte(pdev, 0x9c, &val);
 		base = val >> 3 << 27;
 	}
-	base -= dev_priv->mm.gtt->gtt_stolen_entries << PAGE_SHIFT;
+	base -= dev_priv->mm.gtt->stolen_size;
 #endif
 
 	return base + offset;
@@ -1168,7 +1168,7 @@
 	unsigned long prealloc_size, gtt_size, mappable_size;
 	int ret = 0;
 
-	prealloc_size = dev_priv->mm.gtt->gtt_stolen_entries << PAGE_SHIFT;
+	prealloc_size = dev_priv->mm.gtt->stolen_size;
 	gtt_size = dev_priv->mm.gtt->gtt_total_entries << PAGE_SHIFT;
 	mappable_size = dev_priv->mm.gtt->gtt_mappable_entries << PAGE_SHIFT;
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 745e46b..b62ff5d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -542,7 +542,7 @@
 
 	struct {
 		/** Bridge to intel-gtt-ko */
-		struct intel_gtt *gtt;
+		const struct intel_gtt *gtt;
 		/** Memory allocator for GTT stolen memory */
 		struct drm_mm stolen;
 		/** Memory allocator for GTT */