This updates the NAND stuff to Linux-3.11-rc1. It is synchronized
as best as we can get:

- locks removed
- The splitting in different files we had to better support different
  features has been dropped. Instead this is now done mostly with the
  use of __maybe_unused

Some barebox adjustments are forward ported, like:

- Allow partial page writes
- Optionally allow to erase bad blocks
- check for all_ff before writing a page

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>