Howdy Ganesh. Thomas is correct - there is little you can do when you rely on 3rd party content such as this. Your options are to either to remove the content or contact OggChat and ask them to address the issue.
I am curious how much of a penalty this actually is, however. As long as this script is not blocking your page load, and as long as your page is not critically dependent on this content, it may be acceptable. PageSpeed warns about all optimizations you can make, but they should be seen as recommendations. If you require OggChat for your site and your site loads acceptably fast, you are free to leave it as is.