Audio: add system usage to audio policy engine schemas am: d2ab30cbe9 am: 2c17a95ff2 am: 8f6b57b5a8

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2719503

Change-Id: Iec47cc5106a744dbd269159697977b669f597e71
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>