samples: check if update is needed

Add a ct-ng action to check if samples needs being updated.
This will be usefull when the config options change.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

reporter_name="Nye Liu"

reporter_url="http://sourceware.org/ml/crossgcc/2008-10/msg00046.html"

reporter_comment=""