[PATCH] USB: better usbnet zaurus/mdlm/... fix

This is a somewhat more comprehensive fix for the problem of devices
like the newer Zaurii ... or in this case some Motorola cell phones.

To recap, the problem's root cause is that these devices aren't using
standard USB class specifications for their network links, and so far
we've had to add lots of device-specific driver entries.  The vendor
fix abuses the CDC MDLM descriptors (they _could_ have conformed to
the spec, but didn't) and defines a "Belcarra firmware" pseudo-class.

This patch recognizes that pseudo-class by the GUIDs in those descriptors,
and handles the devices that just use the Zaurus framing.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>