drm/ttm: revert "implement LRU add callbacks v2"

The additional housekeeping had too much CPU overhead,
let's use the BO priorities instead.

agd: also revert hibmc changes

Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-and-Tested-by: Roger.He <Hongbo.He@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ast/ast_ttm.c

@@ -236,8 +236,6 @@ struct ttm_bo_driver ast_bo_driver = {
 	.verify_access = ast_bo_verify_access,
 	.io_mem_reserve = &ast_ttm_io_mem_reserve,
 	.io_mem_free = &ast_ttm_io_mem_free,
-	.lru_tail = &ttm_bo_default_lru_tail,
-	.swap_lru_tail = &ttm_bo_default_swap_lru_tail,
 };
 
 int ast_mm_init(struct ast_private *ast)