msm-qdsp6v2: 2-ways recording support

[https://code.google.com/p/2-way-call-recording/source/browse/patches/msm8974_stereo.patch]

r19 by heinz.teutsch on May 16, 2014   Diff
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.