Add a generic (dtsi) include file for MOXA ART SoCs.

Also add a file for UC-7112-LX.
Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>