omap3: nand: making ecc layout as compatible with romcode ecc

This patch overrides nand ecc layout and bad block descriptor (for 8-bit
device) to support hw ecc in romcode layout. So as to have in sync with ecc
layout throughout; i.e. x-loader, u-boot and kernel.

This enables to flash x-loader, u-boot, kernel, FS images from kernel itself
and compatiable with other tools.

This patch does not enables this feature by default and need to pass from
board file to enable for any board.

Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>