Fix SPDX identifiers

Make this match the project spec.

Change-Id: I8fbcd9816c1f1ae621d18cdea6abd09c3143b64c
diff --git a/gpio.hpp b/gpio.hpp
index 09d479e..f169943 100644
--- a/gpio.hpp
+++ b/gpio.hpp
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: Apache-2.0
-// SPDX-FileCopyrightText: 2025 NVIDIA
+// SPDX-FileCopyrightText: Copyright OpenBMC Authors
 
 #pragma once