The original code needed some updates to work properly with
the USB Device Controller found in Intel's PXA 2xx processors.

  - SET_INTERFACE and SET_CONFIGURATION involve hardware
    automagic:  all endpoints get reset.  This is a PITA,
    and will likely get more work.  (Seems like the reset
    is only partial, hosts need to CLEAR_HALT themselves...)

    What this does is to handle -ECONNABORTED notifications
    from pxa2xx_udc, in those cases.  In general, gadget
    drivers need to reset endpoints themselves, since the
    lower levels (hardware!) won't know how the endpoints
    are allocated between interfaces and altsettings.

  - The config symbol will be CONFIG_USB_PXA2XX, since the
    same controller (modulo errata) is in several processors
    other than the "older" pxa250.

  - This also adds an "i/o pattern" parameter, so that it
    can continue to use the "all zeroes" pattern or switch
    to something else.  The initial "something else" is an
    easily predicted "mod63" pattern.