It's tempting, because usbdevice_create() is so simple to use.  But
there's a lot of unwanted complexity behind the simple interface.
Switch to usb_create_simple().

Cc: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>