ALSA: hdac_ext: add hdac extended controller

The controller needs to support the new capabilities and allow
reading, parsing and initializing of these capabilities, so this patch
does it

Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>