link_power_policy_management default to max_performance

The kernel default for `link_power_management_policy` is `"max_performance"`.
This commit:
https://github.com/NixOS/nixpkgs/commit/f169f60575bec7c61626af180cae364d321b4bec
set the NixOS default to `"min_performance"`.

This issue (https://github.com/NixOS/nixpkgs/issues/11276) details my long
journey to discover this after several file system failures incorrectly
attributed to `TRIM` and `NCQ` settings.

I think we should use the kernel default of `"max_performance"` to assure
the best experience for new users with SSDs and to conform to the defaults of
the kernel and other distros.