Added new locking init requirement for v8.x

The application must call void __iar_Initlocks(void); before any
lock is used.

Author: Deepika

rtos/mbed_boot.c

@@ -579,6 +579,11 @@ void pre_main(void)
     if (low_level_init_needed) {
         __iar_dynamic_initialization();
     }
+
+#if (__IAR_SYSTEMS_ICC__ >= 8)
+    __iar_Initlocks();
+#endif
+
     mbed_main();
     main();
 }