am d2124b7c: am 7e997388: am b5e21103: Merge "AArch64: Use LDXR/STXR instead of LDAXR/STLXR for bionic_atomic_cmpxchg()"

* commit 'd2124b7c5ca15cb593c824d2488f6a95dce4a519':
  AArch64: Use LDXR/STXR instead of LDAXR/STLXR for bionic_atomic_cmpxchg()