[MTD] [NAND] Change NDFC driver to support 405 platforms too

This patch adds 405 platform support to the 440 NDFC driver. The new
AMCC 405EZ PPC is equipped with the same NDFC core as the 440EP(x)
and other will follow soon.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>