Add snd-usb-caiaq driver to support caiaq usb-audio devices from
Native Instrument:
* Native Instruments RigKontrol2
* Native Instruments Kore Controller
* Native Instruments Audio Kontrol 1
* Native Instruments Audio 8 DJ
Signed-off-by: Daniel Mack
Signed-off-by: Karsten Wiese
Signed-off-by: Takashi Iwai
Signed-off-by: Jaroslav Kysela