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/tests/convos.nix

@@ -0,0 +1,30 @@
+import ./make-test-python.nix ({ lib, pkgs, ... }:
+
+with lib;
+let
+  port = 3333;
+in
+{
+  name = "convos";
+  meta = with pkgs.lib.maintainers; {
+    maintainers = [ sgo ];
+  };
+
+  nodes = {
+    machine =
+      { pkgs, ... }:
+      {
+        services.convos = {
+          enable = true;
+          listenPort = port;
+        };
+      };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("convos")
+    machine.wait_for_open_port("${toString port}")
+    machine.succeed("journalctl -u convos | grep -q 'Listening at.*${toString port}'")
+    machine.succeed("curl -f http://localhost:${toString port}/")
+  '';
+})