[PATCH] USB: usbnet (6/9) module for Zaurii and compatibles

This moves usbnet support for Zaurus and compatibles into its own module.
Other than exporting a couple of helper functions, this just involved
shuffling some code and updating the comments.

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