drm/ttm: update bulk move object of ghost BO

[Why]
Ghost BO is released with non-empty bulk move object. There is a
warning trace:
WARNING: CPU: 19 PID: 1582 at ttm/ttm_bo.c:366 ttm_bo_release+0x2e1/0x2f0 [amdttm]
Call Trace:
  amddma_resv_reserve_fences+0x10d/0x1f0 [amdkcl]
  amdttm_bo_put+0x28/0x30 [amdttm]
  amdttm_bo_move_accel_cleanup+0x126/0x200 [amdttm]
  amdgpu_bo_move+0x1a8/0x770 [amdgpu]
  ttm_bo_handle_move_mem+0xb0/0x140 [amdttm]
  amdttm_bo_validate+0xbf/0x100 [amdttm]

[How]
The resource of ghost BO should be moved to LRU directly, instead of
using bulk move. The bulk move object of ghost BO should set to NULL
before function ttm_bo_move_to_lru_tail_unlocked.

v2: set bulk move to NULL manually if no resource associated with ghost BO

Fixed: 5b951e4 ("drm/ttm: fix bulk move handling v2")
Signed-off-by: ZhenGuo Yin <zhenguo.yin@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220906084619.2545456-1-zhenguo.yin@amd.com

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -239,6 +239,9 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 	if (fbo->base.resource) {
 		ttm_resource_set_bo(fbo->base.resource, &fbo->base);
 		bo->resource = NULL;
+		ttm_bo_set_bulk_move(&fbo->base, NULL);
+	} else {
+		fbo->base.bulk_move = NULL;
 	}
 
 	dma_resv_init(&fbo->base.base._resv);