iucode-tool: bump to version 2.3.1
Brings several fixes and enhancements. Check the change log at
https://gitlab.com/iucode-tool/iucode-tool/raw/v2.3.1/ChangeLog
Tested on an equipment with Intel C3000 processor.
Signed-off-by: Carlos Santos <casantos@datacom.com.br>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>