I've been chasing problems on a KT333 based system, with
the 8253 southbridge and EHCI 1.0 (!), and this fixes at
least some of them:

   - locking updates:
      * a few routines weren't protected right
      * less irqsave thrashing for schedule lock

   - adds a watchdog timer that should fire when the
     STS_IAA interrupt seems to be missing.

   - gives ports back to companion UHCI/OHCI on rmmod

   - re-enables faulted QH only after all its completion
     callbacks have done their work

   - removes an oops I've seen when usb-storage unlinks
     stuff.  (it seemed confused about error handling, but
     that's not a reason to oops.)

   - minor cleanup:  deadcode rm, etc

Right now the watchdog just barks, and that mechanism might
go away (or into the shared hcd code).  Sometimes the issue
it reports seems to clear up by itself, but sometimes not...