ARM: OMAP2+: craneboard: support NAND device

 This patch enables the NAND device on the AM3517 Craneboard.

 MTD partitions are created as below.
 0x000000000000-0x000000080000 : "X-Loader"
 0x000000080000-0x000000240000 : "U-Boot"
 0x000000240000-0x000000280000 : "U-Boot Env"
 0x000000280000-0x000000780000 : "Kernel"
 0x000000780000-0x000010000000 : "File System"

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>