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 am: fa974e81

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



Change-Id: Ie2648049563f0ed52060b96d8422a846928cedac
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>