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: 3302cd8d am: c5658edc am: 1d7dd2ae

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



Change-Id: Id3cada0e467d3b3a20d6f9f5fee244ac8bb5cef3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>