davinci: omapl138_lcdk: fix bad NAND ECC config

The configuration used to error correction was not in line with what
linux and the ROM code is using. Fix it by using the correct
configuration. Now u-boot and the SPL are able to read correctly
anything written by them.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
Reviewed-by: Tom Rini <trini@konsulko.com>