arm: mvebu: Add SolidRun ClearFog Armada 38x initial support

arm: mvebu: Add SolidRun ClearFog Armada 38x initial support

This patch adds basic support for the SolidRun ClearFog Armada 38x based
board to mainline U-Boot. Supported interfaces / devices are:
- DDR3
- UART
- MMC
- Ethernet port 0 (connected to dedicated PHY)
- I2C

The included DT source was taken from Russell King's ftp server:
http://www.home.arm.linux.org.uk/~rmk/clearfog/

With only minor modifications, like the addition of some aliases and the
"u-boot,dm-pre-reloc" property.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Rabeeh Khoury <rabeeh@solid-run.com>
Cc: Luka Perkov <luka.perkov@sartura.hr>