am b5e21103: Merge "AArch64: Use LDXR/STXR instead of LDAXR/STLXR for bionic_atomic_cmpxchg()"

* commit 'b5e211031b69963a5f72ff369c66dc325a03e740':
  AArch64: Use LDXR/STXR instead of LDAXR/STLXR for bionic_atomic_cmpxchg()