race tests: fix unsupported condition

0xc0170 · 0xc0170 · commit 7aea3bc43ebf · 2017-05-25T14:47:28.000+01:00
Should be true if single thread is defined, then its not
supported.
diff --git a/TESTS/mbed_drivers/race_test/main.cpp b/TESTS/mbed_drivers/race_test/main.cpp
@@ -22,7 +22,7 @@
 #include "SingletonPtr.h"
 #include <stdio.h>
 
-#ifndef MBED_RTOS_SINGLE_THREAD
+#ifdef MBED_RTOS_SINGLE_THREAD
   #error [NOT_SUPPORTED] test not supported for single threaded enviroment
 #endif
 
