disable sys/io.h on more architectures that don't provide it

These platforms were identified when Debian's buildd tried to build
3.4.0-2 on sid:

    https://buildd.debian.org/status/package.php?p=mesaflash

I used the information on this page to get expected `uname -m` output
for different platforms:

    https://wiki.debian.org/ArchitectureSpecificsMemo