[MTD] [NAND] Replace -1 with -EBADMSG in nand error correction code

Magic numerical values are just bad style.  Particularly so when
undocumented.

Signed-off-by: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
4 files changed