[RenderScript] Use OVERRIDE_RS_DRIVER string in the default
implementation.

Bug: 37035983
Test: mm
Test: manually push to sailfish & angler, verify GPU driver successfully
load, and tests are passing.

Change-Id: Ic55c74228e7eae599702365c513009aa3454656b
diff --git a/renderscript/1.0/default/Android.bp b/renderscript/1.0/default/Android.bp
index c4bd1b3..b996969 100644
--- a/renderscript/1.0/default/Android.bp
+++ b/renderscript/1.0/default/Android.bp
@@ -18,4 +18,11 @@
         "libutils",
         "android.hardware.renderscript@1.0",
     ],
+
+    product_variables: {
+        override_rs_driver: {
+            cflags: ["-DOVERRIDE_RS_DRIVER=%s"],
+        },
+    },
+
 }