drm/i915: introduce i915_gem_alloc_object

Just preparation, no functional change.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2f5f741..3836f56 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4967,7 +4967,7 @@
 	struct drm_gem_object *pwrctx;
 	int ret;
 
-	pwrctx = drm_gem_object_alloc(dev, 4096);
+	pwrctx = i915_gem_alloc_object(dev, 4096);
 	if (!pwrctx) {
 		DRM_DEBUG("failed to alloc power context, RC6 disabled\n");
 		return NULL;