display: More fixes for VNDK

Change-Id: I8887ffdde3d6f39f9405dd38e8eaedbb8da2a9b4
diff --git a/Android.bp b/Android.bp
index ef4b3af..7a6b5b6 100644
--- a/Android.bp
+++ b/Android.bp
@@ -18,6 +18,7 @@
 
 cc_library_headers {
     name: "display_headers",
+    vendor_available: true,
     export_include_dirs: [
         "include",
         "libcopybit",