msm8660: disable LPA for now

  * LPA requires some changes to frameworks/av, which have not been
    ported to cm-11.0 yet
  * copy hardware/qcom/audio-caf/msm8660/audio_policy.conf to device tree
    and comment out lpa section
  * remove audio_policy.conf from the PRODUCT_PACKAGES to stop the build env
    from copying it from hardware/qcom/audio-caf/msm8660

Change-Id: I627ba0184d7c484a1d24cc369c9c79f40b217c1a