ARM: dts: orion5x: add device tree for kurobox-pro

Add dts file to support Buffalo/Revogear Kurobox-Pro, which is marvell
orion5x based 3.5" HDD NAS.

It's a quite old product and already discontinued. So there's no
official website for it. But it was an early product which used marvell
orion5x 88F5182 chipset, it's popular in the community.
Some unofficial site:
  - http://buffalo.nas-central.org/wiki/Category:KuroboxPro
  - http://nice.kaze.com/KUROPRO_ProductSpecifications.pdf



This device tree is based on the board file:
  arch/arm/mach-orion5x/kurobox_pro-setup.c
However, the probing order of NAND and JEDEC-Flash are different from
the original board file, this results in incompatible minor number
for a few /dev/mtdX and /dev/mtdblockX devices.
So I still want to keep the board file for the time being.

Signed-off-by: Roger Shimizu <rogershimizu@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>