fix size issue in memp_simple.c

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@886 bbd45198-f89e-11dd-88c7-29a3b14d5316

examples/kernel/memp_simple.c

@@ -74,7 +74,7 @@ int mempool_simple_init()
 	for (i = 0; i < 48; i ++) ptr[i] = RT_NULL;
 
 	/* 初始化内存池对象 */
-	rt_mp_init(&mp, "mp1", &mempool[0], 80, sizeof(mempool));
+	rt_mp_init(&mp, "mp1", &mempool[0], sizeof(mempool), 80);
 
 	/* 创建线程1 */
 	tid1 = rt_thread_create("t1",