Audio: add system usage to audio policy engine schemas am: acd4a677f0 am: 2b10decfc0 am: 9f063339aa

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2689186

Change-Id: Ic3101aa00bd25d5000d6d44214d1c657c76cf5c9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>