Change header to BSD license (pytorch#8428)

(cherry picked from commit 931bb8b)
Signed-off-by: Robert Kalmar <[email protected]>

Author: mergennachin

exir/passes/quantize_io_pass.py

@@ -1,4 +1,9 @@
-# (c) Meta Platforms, Inc. and affiliates. Confidential and proprietary.
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree
+
 import logging
 from typing import Any, Dict, List, Optional, Union