tools/libfdt/fdt_rw: fix SPDX-License-Identifier

Currently, the terms of both licenses (GPL 2.0 and BSD-2-Clause) must be
met.
However, before switching to the SPDX license identifier, the license
information in the file begins with:

"libfdt is dual licensed: you can use it either under the terms of
the GPL, or the BSD license, at your option."

Therefore, the missing "OR" between the licenses is added.

Fixes: 3508476 ("libfdt: SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause")

Signed-off-by: Max Merchel <Max.Merchel@ew.tq-group.com>

tools/libfdt/fdt_rw.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier:	GPL-2.0+ BSD-2-Clause */
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
 #include "fdt_host.h"
 #include "../../scripts/dtc/libfdt/fdt_rw.c"