[MTD] [NAND] Set the fsl elbc ECCM according the settings in bootloader.

The ECCM maybe set in bootloader, Get ECCM settings from the bootloader,
can avoid the image written by bootloader cannot read out by kernel.

But the limitation of doing it this way is that, it could break large page
NAND if it is written with NAND disabled in u-boot and read with NAND
enabled, or vice versa.

Signed-off-by: Jason Jin <Jason.jin@freescale.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>