[PATCH] USB: ethernet gadget learns about pxa2xx udc

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

   - SET_INTERFACE is effectively unusable.  So the driver
     now has a "minimalist" mode, with none of the bells and
     whistles of CDC.

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

For the record, that "minimalist" mode was the original idea
behind this driver ... implementing CDC was a win for interop
since most non-MSFT host operating systems support it already,
without needing a new driver.

There were also a few other minor updates:

   - Net2280:  queue depth shrank a bit, don't use the same
     endpoint numbers for the IN and OUT sides.  (CATC doesn't
     let filters consider direction, just numbers.)

   - Join the Jihad!  Abolish register_netdev()!!  This just
     nests the gadget-private data structures inside the
     netdev data structure, instead of the other way around.

   - Minor cleanups.