Asoc: msm: 8064: Add support for in-call features

- Add support for slimbus rx and tx channels
  between external modem and APQ.
- Use the slimbus rx channel to route audio packets
  from APQ to external modem for music delivery to
  far-end during a voice call.
- Use the slimbus tx channel to route the voice packets
  from external modem to APQ to record to a file.
- Add mixer control to set mono or stereo recording.

Change-Id: Ice6315de19bf0e2a8d7bd55973976b3c320f1984
Signed-off-by: Helen Zeng <xiaoyunz@codeaurora.org>