Merge "audio flinger: fix initial mmap stream volume" into main am: e3f46d5b

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2829082



Change-Id: I142b8b5d61f18361df85448a7a91fc0e36d89493
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>