Finish plumbing for double RS elements.

Change-Id: Ic708dcaeda4966bb2121ecb6834f56cfa68ad58e
diff --git a/graphics/java/android/renderscript/FieldPacker.java b/graphics/java/android/renderscript/FieldPacker.java
index b6f88be..ff3e22b 100644
--- a/graphics/java/android/renderscript/FieldPacker.java
+++ b/graphics/java/android/renderscript/FieldPacker.java
@@ -124,7 +124,7 @@
         addI32(Float.floatToRawIntBits(v));
     }
 
-    public void addF64(float v) {
+    public void addF64(double v) {
         addI64(Double.doubleToRawLongBits(v));
     }