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

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

Change-Id: I5a4f34089a53ee849c2af5c232bfb982d9025802
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>