[kernel]Delete an extra semicolon

src/idle.c

@@ -44,7 +44,7 @@
 #define _CPUS_NR                1
 #endif /* RT_USING_SMP */
 
-static rt_list_t _rt_thread_defunct = RT_LIST_OBJECT_INIT(_rt_thread_defunct);;
+static rt_list_t _rt_thread_defunct = RT_LIST_OBJECT_INIT(_rt_thread_defunct);
 
 static struct rt_thread idle[_CPUS_NR];
 ALIGN(RT_ALIGN_SIZE)