update copyright header

Signed-off-by: Kebo Liu <[email protected]>

device/mellanox/x86_64-nvidia_sn2201-r0/ACS-SN2201/sai_2201.xml

@@ -1,4 +1,21 @@
 <?xml version="1.0"?>
+<!--
+  Copyright (c) 2019-2021 NVIDIA CORPORATION & AFFILIATES.
+  Apache-2.0
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
 <root>
     <platform_info type="2201">