ASoC: apq8084: Add Incall recording feature support

APQ8084 uses external modem for voice calls and is communicated
with modem through slimbus. Add incall recording support which
uses slimbus6 logical port to record.

Change-Id: I3e73121e79b5e6673e3933cd05b8367921a8e5e7
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>