This USB patch updates the OHCI driver:

  - converts to relying on td_list shadowing the hardware's
    schedule; only collecting the donelist needs dma_to_td(),
    and td list handling works much like EHCI or UHCI.

  - leaves faulted endpoint queues (bulk/intr) disabled until
    the relevant drivers had a chance to clean up.

  - fixes minor bugs (unreported) in the affected code:
      * byteswap problem when unlinking urbs ... symptom would
        be data toggle confusion (since 2.4.2x) on big-endian cpus
      * latent bug if folk unlinked queue in LIFO order, not FIFO

  - removes unnecessary debug code; mostly de-BUG()ged

The interesting fix is the "leave queues halted" one.  As
discussed on email a while back, this HCD fault handling
policy (also followed by EHCI) is sufficient to let device
drivers implement the two key fault handling policies that
seem to be necessary:

    (a) Datagram style, where issues on one I/O won't affect
        the next unless the device halted the endpoint.  The
        device driver can ignore most errors other than -EPIPE.

    (b) Stream style, where for example it'd be wrong to ever
        let block N+1 overwrite block N on the disk.  Once
        the first URB fails, the rest would just be unlinked
        in the completion handler.

As a consequence of using the td_list, you can now see urb
queuing in action in the driverfs 'async' file.  At least, if
you look at the right time, or use drivers (networking, etc)
that queue (bulk) reads for a long time.