yocto/kronos-network-conf: Use S folder for the sources

Currently the kronos-network-conf.bb recipe uses the same folder
for S and WORKDIR, this is giving some issues because the WORKDIR
is not cleaned and changes like remove of files are not performed
and will end up in the deployed image.

So separate S and WORKDIR to fix the issue, while there, suppress
a warning for the licence file.

Update dictionary with a new term.

Signed-off-by: Diego Sueiro <diego.sueiro@arm.com>
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>