Make common x86 arch area for i386 and x86_64 - Take 3

Once again here's an attempt to put the shared files of x86_64 and i386 into a separate directory.

This time, I took the pains to make sure that each patch in this series compiles after it is applied. I did this on both x86_64 as well as i386, with the affected files config options turned on.

I still stayed away from the pci shared code.

This time I moved the speedstep-lib.h into include/asm-x86. Although all references to this files now needs to explicitly state
#include <asm-x86/speedstep-lib.h>
But this will also create a doorway for other shared headers to go into.

And yes the long term goal is to perhaps make a single arch that can handle both the i386 modern CPUs as well as the x86_64 code. And then phase out the x86_64, keeping the current i386 for legacy hardware.

Used git-diff -M for the diffs, so the renames are explicitly stated as such, but no delete/create diff is made (so patch and quilt will not apply theses).

Comments and flames welcome.

-- Steve