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: 2a49ab5b

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



Change-Id: Ic968df04eb6b27e79d1951bbfbe14db9548db382
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>