drm/gem_vram/ttm: move to driver backend destroy function.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200907204630.1406528-10-airlied@gmail.com

drivers/gpu/drm/drm_gem_vram_helper.c

@@ -967,16 +967,12 @@ static const struct drm_gem_object_funcs drm_gem_vram_object_funcs = {
  * TTM TT
  */
 
-static void backend_func_destroy(struct ttm_bo_device *bdev, struct ttm_tt *tt)
+static void bo_driver_ttm_tt_destroy(struct ttm_bo_device *bdev, struct ttm_tt *tt)
 {
 	ttm_tt_fini(tt);
 	kfree(tt);
 }
 
-static struct ttm_backend_func backend_func = {
-	.destroy = backend_func_destroy
-};
-
 /*
  * TTM BO device
  */
@@ -991,8 +987,6 @@ static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
 	if (!tt)
 		return NULL;
 
-	tt->func = &backend_func;
-
 	ret = ttm_tt_init(tt, bo, page_flags);
 	if (ret < 0)
 		goto err_ttm_tt_init;
@@ -1054,6 +1048,7 @@ static int bo_driver_io_mem_reserve(struct ttm_bo_device *bdev,
 
 static struct ttm_bo_driver bo_driver = {
 	.ttm_tt_create = bo_driver_ttm_tt_create,
+	.ttm_tt_destroy = bo_driver_ttm_tt_destroy,
 	.eviction_valuable = ttm_bo_eviction_valuable,
 	.evict_flags = bo_driver_evict_flags,
 	.move_notify = bo_driver_move_notify,