NAND: Add Support for 4K page size in DaVinci NAND driver

This patch adds support for NAND devices with a page size of
4K in the DaVinci NAND driver. The layout matches the layout that TI uses
for 4K page size NAND devices in the kernel NAND driver.

Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>