drm/i915: Rename drm_gem_object_unreference in preparation for lockless free

Ultimately wraps kref_put(), so adopt its nomenclature for consistency
with other subsystems.

s/drm_gem_object_unreference/i915_gem_object_put/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-6-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-5-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 5610394..81f7b43 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -191,17 +191,18 @@
 
 	/* Unbinding will emit any required flushes */
 	while (!list_empty(&eviction_list)) {
-		struct drm_gem_object *obj;
+		struct drm_i915_gem_object *obj;
+
 		vma = list_first_entry(&eviction_list,
 				       struct i915_vma,
 				       exec_list);
 
-		obj =  &vma->obj->base;
+		obj =  vma->obj;
 		list_del_init(&vma->exec_list);
 		if (ret == 0)
 			ret = i915_vma_unbind(vma);
 
-		drm_gem_object_unreference(obj);
+		i915_gem_object_put(obj);
 	}
 
 	return ret;