thermosphere: add proper memory/instruction barriers for breakpoint stuff

thermosphere/src/breakpoints.c

@@ -49,6 +49,7 @@ static void commitAndBroadcastBreakpointHandler(void *p)
 
 static inline void commitAndBroadcastBreakpoints(void)
 {
+    __dmb_sy();
     executeFunctionOnAllCores(commitAndBroadcastBreakpointHandler, NULL, true);
 }
 
@@ -157,4 +158,4 @@ int removeAllBreakpoints(void)
     recursiveSpinlockUnlock(&g_breakpointManager.lock);
 
     return 0;
-}
+}