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/keyboard/uhk.nix

@@ -0,0 +1,21 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+  cfg = config.hardware.keyboard.uhk;
+in
+{
+  options.hardware.keyboard.uhk = {
+    enable = mkEnableOption ''
+    non-root access to the firmware of UHK keyboards.
+      You need it when you want to flash a new firmware on the keyboard.
+      Access to the keyboard is granted to users in the "input" group.
+      You may want to install the uhk-agent package.
+    '';
+
+  };
+
+  config = mkIf cfg.enable {
+    services.udev.packages = [ pkgs.uhk-udev-rules ];
+  };
+}