i386: basic infrastructure support for AMD geode-class machines

This builds upon the existing geode infrastructure, but adds southbridge
support, some GPIO functions, and a header file (asm-i386/geode.h) with some
useful GX/LX detection tests.

The majority of this code was written by Jordan Crouse.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>