Fix license to compatible BSD-2-Clause

OpenSBI is a BSD project. We need to modify some codes to compatible
with BSD-2-Clause license.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Ben Zong-You Xie <ben717@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250728074334.372355-1-wxjstz@126.com
Signed-off-by: Anup Patel <anup@brainfault.org>

platform/generic/include/andes/andes.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+/* SPDX-License-Identifier: BSD-2-Clause */
 /*
  * Copyright (C) 2024 Andes Technology Corporation
  */

platform/generic/include/andes/andes_pma.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+/* SPDX-License-Identifier: BSD-2-Clause */
 /*
  * Copyright (C) 2023 Renesas Electronics Corp.
  */