Motivation for this change

armv7l-hf-multiplatform and aarch64-multiplatform platforms enable the kernelAutoModules option, which enables support for lots of miscellaneous hardware and features. This was missing from the raspberrypi platform.

Things done

This PR adds the options kernelAutoModules=true and kernelPreferBuiltin=true to the raspberrypi platform bringing it in line with the others. Both the mainline and rpi kernels build and run correctly with these options.

cc @dezgeg

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.