drm/ttm: ensure ttm for new node is bound before calling move_notify()

This was true for new TTM_PL_SYSTEM and new TTM_PL_TT cases, but wasn't
the case on TTM_PL_SYSTEM<->TTM_PL_TT moves, which causes trouble on some
paths as nouveau's move_notify() hook requires that the dma addresses be
valid at this point.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -392,10 +392,12 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 	 * Create and bind a ttm if required.
 	 */
 
-	if (!(new_man->flags & TTM_MEMTYPE_FLAG_FIXED) && (bo->ttm == NULL)) {
-		ret = ttm_bo_add_ttm(bo, false);
-		if (ret)
-			goto out_err;
+	if (!(new_man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
+		if (bo->ttm == NULL) {
+			ret = ttm_bo_add_ttm(bo, false);
+			if (ret)
+				goto out_err;
+		}
 
 		ret = ttm_tt_set_placement_caching(bo->ttm, mem->placement);
 		if (ret)