Merge "audio policy: create spatializer mixer only when needed" into tm-dev...

Merge "audio policy: create spatializer mixer only when needed" into tm-dev am: c1e26474 am: 5d6b417f am: 7fe5d496

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/17860127



Change-Id: I664b20775a2afe69afa73a1b24c09ca704e95f09
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>