[android] [vfs] PosixFile: fix large file support on Android

As temporal fix. Influence only on Android.
@koying Could you test it?
This bit is unnecessary.
It's already there, as you can see in a build log (e.g. http://jenkins.kodi.tv/job/Android-ARM/2613/consoleText).

The root issue is that it's ignored by the NDK.