ALSA: usb-audio: move ua101 driver

As part of the USB audio code cleanup, move the non-standard ua101
driver out of the way.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>