Just unrooted my Kindle. Super easy. You will need root to complete it, but it works.
I needed to send my KF2 back to Amazon for a battery defect. Didn't want any problems to go down if they saw the root.
Here is what I did:
Keep root, go to your file explorer and make sure that the system folder is writable, navigate to your /app folder in the system folder, delete the google apps, the google app infrastructure and the SU app. Make sure that you got everything, then do a factory reset. You should now be root free! Congratulations!
Hope that works for you all.