ARM: dts: armada-385-linksys: partition layout is board specific

Move the partition layout to individual boards. The Linksys WRT 3200 ACM
(Rango) comes with a 256MiB nand flash chip and different layout.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>