[ALSA] caiaq - add control API and more input features

 - added support for all input controllers on Native Instrument's 'Kore
   controller'.
 - added ALSA controls to switch LEDs on 'RigKontrol 2', 'RigKontrol3',
   'Audio Kontrol 1' and 'Kore controller'.
 - added ALSA controls to switch input mode, software lock and ground
   lift features on 'Audio 8 DJ'.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>