drm/qxl: fix gaping memory hole

qxl_release_free_list(struct qxl_release *release)

{

	while (!list_empty(&release->bos)) {

		struct ttm_validate_buffer *entry;

		struct qxl_bo_list *entry;

		struct qxl_bo *bo;

		entry = container_of(release->bos.next,

				     struct ttm_validate_buffer, head);

		list_del(&entry->head);

				     struct qxl_bo_list, tv.head);

		bo = to_qxl_bo(entry->tv.bo);

		qxl_bo_unref(&bo);

		list_del(&entry->tv.head);

		kfree(entry);

	}

}