audio: Add 'Void' AIDL type am: b31baae920

Original change: https://android-review.googlesource.com/c/platform/system/hardware/interfaces/+/2296540

Change-Id: I734485f829130ad9e572830a86ce870ab5e30f69
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>