ARM: dts: compulab: add new board description

CompuLab SB-SOM is a multi-module baseboard capable of carrying CM-T43, CM-T54,

and CM-QS600 modules with minor modifications to the SB-SOM assembly.

CompuLab SB-SOM is a multi-module baseboard capable of carrying:

 - CM-T43

 - CM-T54

 - CM-QS600

 - CL-SOM-AM57x

 - CL-SOM-iMX7

modules with minor modifications to the SB-SOM assembly.

Required root node properties:

    - compatible = should be "compulab,sb-som"

Compulab CL-SOM-iMX7 is a miniature System-on-Module (SoM) based on

Freescale i.MX7 ARM Cortex-A7 System-on-Chip.

Required root node properties:

    - compatible = "compulab,cl-som-imx7", "fsl,imx7d";

Compulab SBC-iMX7 is a single board computer based on the

Freescale i.MX7 system-on-chip. SBC-iMX7 is implemented with

the CL-SOM-iMX7 System-on-Module providing most of the functions,

and SB-SOM-iMX7 carrier board providing additional peripheral

functions and connectors.

Required root node properties:

    - compatible = "compulab,sbc-imx7", "compulab,cl-som-imx7", "fsl,imx7d";