Char: moxa, remove static isa support

Static ISA field is empty and probably will never be filled in, remove it.
The driver still supports ISA cards passed through module parameter.  This
actually fixes one bug inside the initialization of module-param passed cards
initialization.

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>