[natty/maverick/oneiric] SRU: fix USB port detection on Dell Studio 1536

[dann frazier]

Two changesets were recently accepted upstream to fix LP #647043, a
regression that broke USB on some laptops starting in maverick (worked
in lucid).

For precise, this is a trivial cherry-pick - I verified the fix in a
test build that Leann prepared, so I believe we're on our way to a fix
there. For oneiric, this is also a trivial cherry-pick, so I'll just
ask that those changes be pulled in as-is.

For natty, the patches needed some minor adjusting, and for maverick
they needed to be modified to deal with some file renames. I'll
follow-up to this thread with backports for each of these.