hal: Do not apply CSD voice switch API on 8960

Introduced by I9239ff21e1c07370516d0ed668e1e94af12f9eb2, not relevant
here.

Change-Id: Icb63ad5dc17029bc79f81051458b47a9ddb00bf5
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_hardware_qcom_audio-caf into cm-11.0