Apply version script to future libcamera2ndk platform lib

Bug: http://b/69603741
Test: make
Change-Id: Idd661042ec837d412a29b1b9b77d642a4a540900
diff --git a/camera/ndk/Android.bp b/camera/ndk/Android.bp
index 838dd4a..7c3a2f0 100644
--- a/camera/ndk/Android.bp
+++ b/camera/ndk/Android.bp
@@ -67,5 +67,6 @@
     export_include_dirs: ["include"],
     export_shared_lib_headers: [
         "libnativewindow",
-    ]
+    ],
+    version_script: "libcamera2ndk.map.txt",
 }