Fix misc-macro-parentheses warnings in testUtil.c.

Bug: 28705665
Change-Id: I709ae08e15e5afb067bf9b208664107a449e1de3
diff --git a/tests/lib/testUtil/testUtil.c b/tests/lib/testUtil/testUtil.c
index 983e7a4..d4dcea2 100644
--- a/tests/lib/testUtil/testUtil.c
+++ b/tests/lib/testUtil/testUtil.c
@@ -32,7 +32,7 @@
 
 #include <cutils/log.h>
 
-#define ALEN(a) (sizeof(a) / sizeof(a [0]))  // Array length
+#define ALEN(a) (sizeof(a) / sizeof((a)[0]))  // Array length
 typedef unsigned int bool_t;
 #define true (0 == 0)
 #define false (!true)