The sound device instance needs to be a child of the USB interface, not
the USB device. Newer udev versions pay attention to that.
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Reported-by: NLennart Poettering <lennart@poettering.net>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>