I don't think you necessarily have to revert anything you have done, assuming you want to keep the code you already pushed. You can simply move the file to a new location and possibly change the name, then push this change to your remote branch. GitHub will automatically detect that your remote branch has been updated and the pull request can then be completed.
Once you have moved the file and renamed it, you can have two options. The first is to simply commit the work and push:
git commit -m 'Renamed file and moved to a new location'
git push origin yourBranch
This will create a new commit on top of your remote branch. The other option would be to amend the HEAD commit, and force push that to the repository:
git commit --amend -m 'Renamed file and moved to a new location'
git push --force origin yourBranch
This will simply update the commit on the HEAD of your remote branch. Regardless of how you want to resolve this, your feature branch will appear in the master
branch as a single merge commit, and your pull request can be completed.