I followed the instructions mentioned in this blog https://www.virtuallyghetto.com/2015/09/how-to-deploy-and-run-the-vsan-6-1-witness-virtual-appliance... from virtuallyghetto blog for William lam and the appliance now is up and running.
in this blog, William lam stated that he plans to share this feedback internally with Engineering and hopefully deploying VSAN Witness in the future can be much more easier when it comes to running it on VMware Fusion and Workstation.
I am not sure if this is the only way to deploy vSAN witness on VMware workstation or I have done something wrong so the direct approach by only importing the ova didn't work properly.