This code is based on:
http://elm-chan.org/fsw/ff/00index_e.html
FatFs Generic FAT File System Module
This patch offers a read/write implementation for barebox. The code
does not exaclty match barebox coding style, but works nicely and
should be ready to give it a try.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>