A simple way to search for creative commons art in DA, is to use Google advance search.
Put it in you google.com search:
"This work is licensed under a Creative Commons" site:deviantart.com
Click the word "Images" in the left of the google page. It will show images instead of pages.
Voila. You'll see all images under CC in DA.
If you want to be more specific in your search, you can add words in the search above.
It doesn't compares with an in-site feature, but at least it is a workaround...