fix compile
qcom: Split off caf AUDIO_VARIANT support from QCOM_HARDWARE

One does not imply the other, add a different flag to allow using
them independently

Change-Id: I7fe0c0391967132a65f86f0c5f4bc0f54d50777d
Merge remote-tracking branch 'cyanogen/cm-10.2' into cm-10.2