chore: remove rpi-cross-overlay — fork nixpkgs-rpi.nix already handles cross-compile

modules/nixos/rpi-cross-overlay.nix

@@ -1,40 +0,0 @@
-# rpi-cross-overlay.nix
-#
-# Override pkgs.rpi to cross-compile when buildPlatform != hostPlatform.
-#
-# By default, nixos-raspberrypi's nixpkgs-rpi module creates pkgs.rpi via
-# mkRpiPkgs which imports nixpkgs with system="aarch64-linux" — a NATIVE
-# aarch64 build that requires QEMU on x86_64 builders.
-#
-# This module detects cross-compilation (buildPlatform != hostPlatform) and
-# re-imports pkgs.rpi using localSystem (builder) + crossSystem (target) so
-# that kernel, firmware, and rpi-optimized packages are genuinely cross-compiled
-# with zero QEMU emulation.
-#
-# Once nixos-raspberrypi upstream supports buildPlatform natively in mkRpiPkgs,
-# this module can be removed.
-
-{ config, lib, pkgs, nixos-raspberrypi, ... }:
-
-let
-  inherit (config.nixpkgs) buildPlatform hostPlatform;
-  isCross = buildPlatform.system != hostPlatform.system;
-in
-lib.mkIf isCross {
-  nixpkgs.overlays = [
-    (final: prev: {
-      rpi = import pkgs.path {
-        localSystem = { system = buildPlatform.system; };
-        crossSystem = { system = hostPlatform.system; };
-        overlays = with nixos-raspberrypi.overlays; [
-          bootloader
-          vendor-kernel
-          vendor-firmware
-          kernel-and-firmware
-          vendor-pkgs
-          pkgs
-        ];
-      };
-    })
-  ];
-}