audio: Update ChildInterface to set scheduler policy lazily am: 780fefb331

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2674338

Change-Id: Ia6ae775532cfad6d1e5d9bf0a614545be5cc1ef7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>