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/misc/nixpkgs/test.nix

@@ -0,0 +1,8 @@
+{ evalMinimalConfig, pkgs, lib, stdenv }:
+lib.recurseIntoAttrs {
+  invokeNixpkgsSimple =
+    (evalMinimalConfig ({ config, modulesPath, ... }: {
+      imports = [ (modulesPath + "/misc/nixpkgs.nix") ];
+      nixpkgs.system = stdenv.hostPlatform.system;
+    }))._module.args.pkgs.hello;
+}