Merge "Revert "mmap write/read returns non-zero when writing successfully"" am: 9ea8b0dbb4 am: 28ebff3ba6 am: 62217f1b18

Original change: https://android-review.googlesource.com/c/platform/external/tinyalsa/+/1519782

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I31add29a3e5988213d8733a32f3d83c1843d6fde