Char: moxa, pci io space fixup

- request region before remapping pci io space
- use ioremap, iounmap istead of iomap interface, because we use
  readX/writeX for accessing this space because of isa support

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>