audio: Clarify "bus" device type am: 467b81d597 am: 4f852b749d am: f467c26d6c

Original change: https://android-review.googlesource.com/c/platform/system/hardware/interfaces/+/2858105

Change-Id: Iff18dc1a35a1366d0d88995b2f9e82a8fe55d606
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>