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/coturn.nix

@@ -0,0 +1,29 @@
+import ./make-test-python.nix ({ ... }: {
+  name = "coturn";
+  nodes = {
+    default = {
+      services.coturn.enable = true;
+    };
+    secretsfile = {
+      boot.postBootCommands = ''
+        echo "some-very-secret-string" > /run/coturn-secret
+      '';
+      services.coturn = {
+        enable = true;
+        static-auth-secret-file = "/run/coturn-secret";
+      };
+    };
+  };
+
+  testScript =
+    ''
+      start_all()
+
+      with subtest("by default works without configuration"):
+          default.wait_for_unit("coturn.service")
+
+      with subtest("works with static-auth-secret-file"):
+          secretsfile.wait_for_unit("coturn.service")
+          secretsfile.succeed("grep 'some-very-secret-string' /run/coturn/turnserver.cfg")
+    '';
+})