Fix SPDX identifiers

Make this match the project spec.

Change-Id: I8fbcd9816c1f1ae621d18cdea6abd09c3143b64c
diff --git a/gpio.cpp b/gpio.cpp
index d4b2d1b..cb14294 100644
--- a/gpio.cpp
+++ b/gpio.cpp
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: Apache-2.0
-// SPDX-FileCopyrightText: 2025 NVIDIA
+// SPDX-FileCopyrightText: Copyright OpenBMC Authors
 
 #include "gpio.hpp"