ASoC: wcd934x: add MAD support for wcd934x codec

MAD (Microphone Activity Detection) hardware block in wcd934x audio
codec samples the microphone at configured intervals to sense
presence of valid audio signal. This is used for voice activation
use cases. Change adds widgets and routes to enable the MAD block.

CRs-Fixed: 1049012
Change-Id: I1ce4f3f215850fada6c25192a4351f3a9c76a370
Signed-off-by: Meng Wang <mwang@codeaurora.org>
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>