Remove an obsolete compatibility macro.

Change-Id: Ibeae0986b6c68f40e414917405a31cc0ad810fc4
diff --git a/include/cutils/atomic.h b/include/cutils/atomic.h
index d7c4a35..3866848 100644
--- a/include/cutils/atomic.h
+++ b/include/cutils/atomic.h
@@ -120,7 +120,6 @@
  */
 #define android_atomic_write android_atomic_release_store
 #define android_atomic_cmpxchg android_atomic_release_cas
-#define android_atomic_swap android_atomic_release_swap
 
 #ifdef __cplusplus
 } // extern "C"