Common warnings

[Jean-Christophe PLAGNIOL-VILLARD]

> 
> There are also a large number of slightly different warnings coming
> from the numerous different AT91 configurations.
Will try to take a look on it
> Can the maintainers
> perhaps look at consolidating some of the AT91 configurations!
I'm curently working on it and also allow to run all sam9 in one kernel only
but it will be for next release

Best Regards,
J.