Merge "Remove unused mutex fields" into main am: d981b60fbe

Original change: https://android-review.googlesource.com/c/platform/system/extras/+/2909477

Change-Id: Ib10decdbec8993984b0289246ee03065395254d6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>