Disable powertop (conflicts with TLP)

Source: https://linrunner.de/tlp/faq/powertop.html
Proof that powertop is called with --auto-tune: 
https://github.com/TechsupportOnHold/Batterylife/blob/main/laptop.nix#L23
https://github.com/NixOS/nixpkgs/blob/2c8d3f48d33929642c1c12cd243df4cc7d2ce434/nixos/modules/tasks/powertop.nix#L64