This patch creates the first of several separate "minidriver" modules
for "usbnet".  This one handles only the very simplest hardware, which
can be handled almost entirely by the "usbnet" core.

    - Move device-specific bits into new "cdc_subset.c" driver,
      shrinking "usbnet" by a bunch;

    - Export the functions needed to support this minidriver
      (with EXPORT_SYMBOL_GPL);

    - Update Kconfig and kbuild accordingly.

This one handles about a dozen different device types, with the most
notable ones being Gumstix and most Linux-based PDAs (except Zaurus
running that ancient code from Sharp).
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This starts to prepare the core of "usbnet" to know less about various
framing protocols that map Ethernet packets onto USB, so "minidrivers"
can be modules that just plug into the core.

  - Remove some framing-specific code that cluttered the core:

      * net->hard_header_len records how much space to preallocate;
        now drivers that add their own framing (Net1080, GeneLink,
	Zaurus, and RNDIS) will have smoother TX paths.  Even for
	the drivers (Zaurus, Net1080) that need trailers.

      * defines new dev->hard_mtu, using this "hardware" limit to
        check changes to the link's settable "software" mtu.

      * now net->hard_header_len and dev->hard_mtu are set up in the
        driver bind() routines, if needed.

  - Transaction ID is no longer specific to the Net1080 framing;
    RNDIS needs one too.

  - Creates a new "usbnet.h" header with declarations that are shared
    between the core and what will be separate modules.

  - Plus a couple other minor tweaks, like recognizing -ESHUTDOWN
    means the keventd work should just shut itself down asap.

The core code is only about 1/3 of this large file.  Splitting out the
minidrivers into separate modules (e.g. ones for ASIX adapters,
Zaurii and similar, CDC Ethernet, etc), in later patches, will
improve maintainability and shrink typical runtime footprints.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Updates to the usbnet driver:

 - Remove a warning when built with Zaurus support but not CDC Ethernet;
   just moves an #ifdef to cover more code

 - Two tweaks to the pseudo-MDLM support:
    * correctly handle _either_ of the two GUIDs
    * ignore a padding bit that doesn't seem necessary

 - Remove ID for one Motorola phone that uses the MDLM stuff.

It also updates the Kconfig helptext to make it clearer that the "Zaurus"
configuration option supports an increasing (sigh) family of nonstandard
peripheral protocols.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!