ARM: mvebu: Enable NAND controller in ReadyNAS 102 .dts file

Now that NAND controller support is available for Armada 370
(cb28e253: ARM: mvebu: Add support for NAND controller in
Armada 370/XP), this patch enables support for ReadyNAS 102 and
defines default partition layout as delivered by NETGEAR.

As described in similar commits 2be2bc39 (ARM: mvebu: Enable
NAND controller in Armada XP GP board) and d8c552dd

 (ARM:
mvebu: Enable NAND controller in Armada 370 Mirabox),
"marvell,keep-config" parameter is used as current support does
not allow for setting of timing parameters yet.

Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>