[PATCH] USB: ohci misc updates

[PATCH] USB: ohci misc updates

Mostly from Benjamin Herrenschmidt:

  - prevent usbcore from asking the HCD root hub code
    to read registers on one more suspend path (some
    hardware gets upset in those cases);

  - try handling a "device died" cleanup case better

  - add some wmb() calls in spots that could matter
    on some hardware