AudioFlinger: Update MmapThread annotations

Test: atest AudioTrackTest AudioRecordTest
Test: atest AAudioTests AudioTrackOffloadTest
Test: atest AudioPlaybackCaptureTest
Test: Camera YouTube
Bug: 275748373
Merged-In: I748c2c17fd220ad2b5c5d2574077fa1c409476b5
Change-Id: I748c2c17fd220ad2b5c5d2574077fa1c409476b5
3 files changed