arm: mvebu: Add Helios4 Armada 38x initial support

The helios4 is built on the SolidRun Armada 38x SOM.
The port os based on the ClearFog board, using information from
https://github.com/helios-4/u-boot-marvell as well as dtb input
from https://github.com/helios-4/linux-marvell



Signed-off-by: Dennis Gilmore <dennis@ausil.us>
Signed-off-by: Dennis Gilmore <dgilmore@redhat.com>
Signed-off-by: Stefan Roese <sr@denx.de>