Fix build error.

Change-Id: Ife0ec056c33654a56f270a5673f614820cfc2e29
diff --git a/graphics/java/android/renderscript/FieldPacker.java b/graphics/java/android/renderscript/FieldPacker.java
index a9d0180..d166972 100644
--- a/graphics/java/android/renderscript/FieldPacker.java
+++ b/graphics/java/android/renderscript/FieldPacker.java
@@ -245,7 +245,7 @@
     }
 
     public void addBoolean(Boolean v) {
-        addI8(v ? 1 : 0);
+        addI8((byte)(v ? 1 : 0));
     }
 
     public final byte[] getData() {