Fix misc-macro-parentheses warnings in hwui and graphic jni.

Bug: 28705665
Change-Id: I7d1eb38a713fe6cc7f41a3cc3f2f9d0aa0114b2c
diff --git a/libs/hwui/Matrix.cpp b/libs/hwui/Matrix.cpp
index 06e67c0..872abde 100644
--- a/libs/hwui/Matrix.cpp
+++ b/libs/hwui/Matrix.cpp
@@ -425,7 +425,7 @@
     vec.z = orig.x * data[2] + orig.y * data[6] + orig.z * data[kScaleZ] + data[kTranslateZ];
 }
 
-#define MUL_ADD_STORE(a, b, c) a = (a) * (b) + (c)
+#define MUL_ADD_STORE(a, b, c) ((a) = (a) * (b) + (c))
 
 void Matrix4::mapPoint(float& x, float& y) const {
     if (isSimple()) {