stereo call recording support

Patch that allows for call recording in
stereo (left channel: TX; right channel:
RX). Tested on Nexus 5 (MSM8974). Likely
works on other recent MSM chipsets as
well.

Change-Id: I3f67ee5b83383f09b339f0af710b470f8a3a000c
Merge pull request #1 from CyanogenMod/cm-11.0

stereo call recording support