Unless, we get a licence this problem wont be solved.
But, by default the grace period will be 120. That can be renewed by doing the below process.
Delete the REG_BINARY in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod
In GracePeriod, leave the Default as it is.
Reboot the machine.
I have got this solution from the below mentioned URL and it worked out.
http://www.360ict.nl/blog/no-remote-desktop-licence-server-availible-on-rd-session-host-server-2012/
Every 119 days we need to delete the key. So that we will get another 120 grace period.