MXC: Add large page oob layout for i.MX31 NAND controller.

Import the large page oob layout from Linux mxc_nand.c driver.

The CONFIG_SYS_NAND_LARGEPAGE option is used to activate
the large page oob layout. Run time detection is not supported
as this moment.

This has been tested on the i.MX31 PDK board with a large
page NAND device.

Signed-off-by: Magnus Lilja <lilja.magnus@gmail.com>