ARM: dts: da850-lcdk: Add NAND to DT

This adds DT support for the NAND connected to the SoC AEMIF.
Passed torture hashing a 40MB file on top of UBIFS using subpages.

Signed-off-by: Karl Beldan <kbeldan@baylibre.com>
[khilman: add back default partitions from an earlier patch]
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>