ARM: dts: compulab: add new board description

Add description for newly introduced Compulab devices:
- CL-SOM-iMX7
- SBC-iMX7

Signed-off-by: Ilya Ledvich <ilya@compulab.co.il>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>