x86: geode: MSR cleanup

This cleans up a few MSR-using drivers in the following manner:
  - Ensures MSRs are all defined in asm/geode.h, rather than in misc
    places
  - Makes the naming consistent; cs553[56] ones begin with MSR_,
    GX-specific ones start with MSR_GX_, and LX-specific ones start
    with MSR_LX_.  Also, make the names match the data sheet.
  - Use MSR names rather than numbers in source code
  - Document the fact that the LX's MSR_PADSEL has the wrong value
    in the data sheet.  That's, uh, good to note.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>