Char: moxa, merge c2xx and c320 firmware loading

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Tested-by: Oyvind Aabling <Oyvind.Aabling@uni-c.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>