scripts: add update_ngen.sh

scripts/update_ngen.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+#===============================================================================
+# Copyright 2025 Intel Corporation
+#
+# 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.
+#===============================================================================
+
+if [ -z "$1" ]; then
+    echo "Script for nGEN downstreaming."
+    echo "Usage: $0 <nGEN git repository address>"
+    exit 0
+fi
+
+set -e
+rm -rf third_party/ngen
+git clone $@ third_party/ngen
+./third_party/ngen/scripts/public.sh
+git checkout third_party/ngen/COPYRIGHT
+rm -rf third_party/ngen/{.git,scripts}
+echo "Update completed."