Add @UnsupportedAppUsage annotations

For packages:
  android.renderscript

This is an automatically generated CL. See go/UnsupportedAppUsage
for more details.

Exempted-From-Owner-Approval: Mechanical changes to the codebase
which have been approved by Android API council and announced on
android-eng@

Bug: 110868826
Test: m
Change-Id: I016f6e720e79c48afe44f4690b5dd99fc81ae780
Merged-In: I1aa8ebca448547031b426a7b305c5c3d6fcf2652
diff --git a/rs/java/android/renderscript/Matrix4f.java b/rs/java/android/renderscript/Matrix4f.java
index 5d5bf5f..026c9fb 100644
--- a/rs/java/android/renderscript/Matrix4f.java
+++ b/rs/java/android/renderscript/Matrix4f.java
@@ -16,6 +16,7 @@
 
 package android.renderscript;
 
+import android.annotation.UnsupportedAppUsage;
 import java.lang.Math;
 
 
@@ -489,5 +490,6 @@
         }
     }
 
+    @UnsupportedAppUsage
     final float[] mMat;
 }