commit 7a2c07d29b "kmod: enable on darwin" added darwin
support mostly for `depmod` to be able to build `linux` kernel
on `darwin`.
In version 30 kmod requires more and more linux syscalls to build.
Instead of patching it for darwin let's drop it's support instead.
Maybe `depmod` could be packaged using some other way if needed.
Related: https://github.com/NixOS/nixpkgs/pull/182720 removed
`kmod` use on `darwin` from rare packages that still pulled it in.
65b9c17842