Make mIsDeviceLockedForUser synchronized. am: 8696c2ca1b am: 19e17f0981 am: f7d50266fc am: 6261b5e6b3

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/security/+/12855595

Change-Id: Ia7b1de462d0ae491a2a338f7805c1ffdf142ad43