Merge "libaudiohal: mmap playback support" am: 88e189e8b3 am: ed2e7d7f6d

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2514035

Change-Id: Ib03855c19bb3b40d4649732d1b35d823635eab75
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>