So I assume you mean that you will be leaving the nameservers for the domain pointed to godaddy's.
You can pay for a dedicated IP if you want, it still doesn't technically guarentee that the IP won't change but it's unlikely.
You can also do this without the dedicated IP by adding the domain as fully hosted in the dreamhost panel under manage domains. After adding the domain you will see a little clock icon by the domain name for 10 or 15 minutes. Refresh the page after about 15 minutes and make sure that icon is gone. Then you can click the DNS link right under the domain, and on the page that loads the very first entry in the "non-editiable entries for DOMAINNAME" should be an A record with an IP adddress, you can use that IP address to set in your advanced DNS at godaddy. Just be aware that if the site breaks in the future the first thing to check is that IP address. (IP's really don't change often.)