layer.conf: Add in useradd dependencies as ABISAFE dependencies
Currently allarch recipes using useradd rebuild each time MACHINE
changes which is not desireable. Adding the useradd dependencies
to this list ensures they do not change under these circumstances.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org> Signed-off-by: Steffen Sledz <sledz@dresearch-fe.de> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
