fixes cub namespace

Author: elstehle

cub/cub/detail/segmented_params.cuh

@@ -1,8 +1,6 @@
 // SPDX-FileCopyrightText: Copyright (c) 2025, NVIDIA CORPORATION. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-CUB_NAMESPACE_BEGIN
-
 #pragma once
 
 #include <cub/config.cuh>
@@ -19,6 +17,8 @@ CUB_NAMESPACE_BEGIN
 #include <cuda/std/iterator>
 #include <cuda/std/limits>
 
+CUB_NAMESPACE_BEGIN
+
 namespace detail::params
 {
 // -----------------------------------------------------------------------------