Fix misc-macro-parentheses warnings.

Bug: 28705665
Change-Id: I97d1dec9a4397fd7a3cab5180a833066b8abe0ab
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 7d2d550..595c543 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -96,7 +96,7 @@
 }
 
 #ifndef ARRAY_SIZE
-#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 #endif
 
 namespace android {