board: cssi: Add MIAE & VGoIP devices

This adds support for the MIAE and VGoIP devices.
Those devices have the same CPU board that the MCR3000_2G board.

The devices are very modular, they are provided with
interchangeable front and back panels.

Linux kernel is shipped with a device tree which contains all
possible setups, and U-boot eliminates unrelated nodes based on
detected hardware.

This patch was originally written by Charles Frey who's
email address is not valid anymore as he left the company.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: FRANJOU Stephane <stephane.franjou@csgroup.eu>