Revert "Remove incorrect android_atomic_...64 use."

This reverts commit 88b7541d682a6ad402eff15e58c9c792497096d7.

Change-Id: Ie701c308451a3697bb167aff119318b932133f90
diff --git a/include/binder/Binder.h b/include/binder/Binder.h
index 16f2c4a..ba3ac4b 100644
--- a/include/binder/Binder.h
+++ b/include/binder/Binder.h
@@ -17,7 +17,6 @@
 #ifndef ANDROID_BINDER_H
 #define ANDROID_BINDER_H
 
-#include <stdatomic.h>
 #include <binder/IBinder.h>
 
 // ---------------------------------------------------------------------------
@@ -70,7 +69,7 @@
 
     class Extras;
 
-    atomic_uintptr_t    mExtras;  // should be atomic<Extras *>
+            Extras*     mExtras;
             void*       mReserved0;
 };