Since https://github.com/NixOS/nixpkgs/pull/302300 is merged,
hardware.firmware are now compressed with zstd. On my oneplus-enchilada,
this is causing the WLAN interface disappearing. This PR fixes that by
copying the changes of kernel config from NixOS/nixpkgs#302300
Turns out nvim has a tab limit, so I didn't get all of them last time.
- Remove the last usages of URL literals
- All unused variables and arguments (the only exceptions are module
args and lib) are removed
- Clean up a couple more unused recs