pylibfdt: Replace dual GPLv2/BSD license boilerplate with SPDX tags

Replace pylibfdt GPLv2/BSD license boilerplate and add missing license
with SPDX tags.

Signed-off-by: Rob Herring <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: David Gibson <[email protected]>
diff --git a/pylibfdt/setup.py b/pylibfdt/setup.py
index 9e84359..a00bf8b 100755
--- a/pylibfdt/setup.py
+++ b/pylibfdt/setup.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python2
+# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
 
 """
 setup.py file for SWIG libfdt