There are two ways as follow to point your domain to your Amazon EC2 server as follow:
 Use Godaddy’s DNS service
Since your domain is registered with Godaddy, you can continue using their DNS service and point “A” record for your website to your Amazon Ec2 server.
You will have to update “A” record for the following:
@ A Your Amazon Ec2 server IP
WWW A Your Amazon Ec2 server IP
If you have additional subdomains, you will need to add “A” record for them as well.
 Use Amazon’s DNS service
If it is possible to setup DNS server on your Amazon Ec2 server, you can add DNS server and register your private nameservers from your Godaddy’s control panel.
This will allow you to use your own DNS (like ns1.yourdomain.com and ns2.yourdomain.com). Please note that before you use your private namservers, you will have to register them from your Godaddy’s control panel.