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: a3a217bd am: 0bae8b75

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



Change-Id: I5644533b14bbb920ad7da1fe370a8a4facbd33ec
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>