Fix misc-macro-parentheses warnings in opengl.

Bug: 28705665
Change-Id: I761d310f0dff182c288cdbb5371272f4833aa282
diff --git a/opengl/tests/hwc/hwcStress.cpp b/opengl/tests/hwc/hwcStress.cpp
index b1d6c76..e6e5194 100644
--- a/opengl/tests/hwc/hwcStress.cpp
+++ b/opengl/tests/hwc/hwcStress.cpp
@@ -161,7 +161,7 @@
 #define CMD_STOP_FRAMEWORK   "stop 2>&1"
 #define CMD_START_FRAMEWORK  "start 2>&1"
 
-#define NUMA(a) (sizeof(a) / sizeof(a [0]))
+#define NUMA(a) (sizeof(a) / sizeof((a)[0]))
 #define MEMCLR(addr, size) do { \
         memset((addr), 0, (size)); \
     } while (0)