Adjust this code so that it can work with Python 2 and 3.
Fixes: d73fcb1 (moveconfig: Support building a simple config database)
Reported-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
An early version of this is available upstream. Bring it in as a starting
point. This is from dtc upstream commit e56f2b0.
Future work will plumb it into dtoc and remove the now-unnecessary local
libraries.
Signed-off-by: Simon Glass <sjg@chromium.org>