Selectively include support for port I/O

This re-factors port IO to make it easier to omit it on certain
platforms that don't support it:

- Add a Kconfig variable, CONFIG_INTF_PORT_IO, which defaults to 'y'
  for x86 and 'n' otherwise. ARM actually has <sys/io.h> which
  declares inb/outb/etc, but we don't actually use it. We can select
  it on an as-needed basis.

- Modify intf/io.c to only compile support for the raw port IO
  interface if the Kconfig variable is defined (selected).

- Opportunistically move inclusion of <sys/io.h> to intf/io.c where
  stuff that's defined in <sys/io.h> is used.

TEST=emerge-mipsel-o32-generic mosys works

Change-Id: I4e0e4ef0b8add0b897e08bc7ab95637e8be85810
Reviewed-by: Shawn Nematbakhsh <>
Commit-Queue: David Hendricks <>
Tested-by: David Hendricks <>
4 files changed