Get 6600 XT Working on Ubuntu

This is a follow up to Wendell's video. Wanted to add some clarity and help people out. Wendell's Video - https://www.youtube.com/watch?v=VSXftsxBpi0 AskUbuntu question - https://askubuntu.com/a/1350260/37577 Latest Mesa PPA - https://launchpad.net/~kisak/+archive/ubuntu/kisak-mesa