arm: Replace __sync_synchronize() implementation

cpukit/score/cpu/arm/armv4-sync-synchronize.c

@@ -1,9 +1,20 @@
-void
-__sync_synchronize (void)
+/*
+ * Copyright (c) 2015 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#include <rtems/score/cpu.h>
+
+void __sync_synchronize( void )
 {
-#ifdef ARM_MULTILIB_HAS_BARRIER_INSTRUCTIONS
-  asm volatile("dmb" : : : "memory");
-#else
-  asm volatile("" : : : "memory");
-#endif
-}
+  _ARM_Data_memory_barrier();
+}