uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/modules/hardware/network/ath-user-regd.nix

@@ -0,0 +1,31 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+  kernelVersion = config.boot.kernelPackages.kernel.version;
+  linuxKernelMinVersion = "5.8";
+  kernelPatch = pkgs.kernelPatches.ath_regd_optional // {
+    extraConfig = ''
+      ATH_USER_REGD y
+    '';
+  };
+in
+{
+  options.networking.wireless.athUserRegulatoryDomain = mkOption {
+    default = false;
+    type = types.bool;
+    description = ''
+      If enabled, sets the ATH_USER_REGD kernel config switch to true to
+      disable the enforcement of EEPROM regulatory restrictions for ath
+      drivers. Requires at least Linux ${linuxKernelMinVersion}.
+    '';
+  };
+
+  config = mkIf config.networking.wireless.athUserRegulatoryDomain {
+    assertions = singleton {
+      assertion = lessThan 0 (builtins.compareVersions kernelVersion linuxKernelMinVersion);
+      message = "ATH_USER_REGD patch for kernels older than ${linuxKernelMinVersion} not ported yet!";
+    };
+    boot.kernelPatches = [ kernelPatch ];
+  };
+}