The U-Boot NAND booting support is now extended to support ECC
upon loading of the NAND U-Boot image.

Tested on AMCC Sequoia (440EPx) and Bamboo (440EP).

Signed-off-by: Stefan Roese <sr@denx.de>

Patch by Stefan Roese, 12 Sep 2006

- Add support for PPC440EPx & PPC440GRx
- Add support for PPC440EP(x)/GR(x) NAND controller
  in cpu/ppc4xx directory
- Add NAND boot functionality for Sequoia board,
  please see doc/README.nand-boot-ppc440 for details
- This Sequoia NAND image doesn't support environment
  in NAND for now. This will be added in a short while.
Patch by Stefan Roese, 07 Sep 2006