audio: add OWNERS for the README.md am: 6a9f697d am: c812fbf2 am: 07ec63d3 am: 7117600c

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2169871



Change-Id: Ide3a72fbdea6d2021c37f21d747a7a363e9bee0a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>