Add machine file for Olimex A20-SOM204-EVB board. It is an expansion board
for the Olimex A20-SOM204 SOM that uses the sun7i Allwinner A20 Soc.
It is supported in U-Boot and mainline Linux kernel.
Signed-off-by: Ovidiu Panait <ovidiu.panait.oss@gmail.com>
