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/docker-tools-cross.nix

@@ -0,0 +1,76 @@
+# Not everyone has a suitable remote builder set up, so the cross-compilation
+# tests that _include_ running the result are separate. That way, most people
+# can run the majority of the test suite without the extra setup.
+
+
+import ./make-test-python.nix ({ pkgs, ... }:
+let
+
+  remoteSystem =
+    if pkgs.stdenv.hostPlatform.system == "aarch64-linux"
+    then "x86_64-linux"
+    else "aarch64-linux";
+
+  remoteCrossPkgs = import ../.. /*nixpkgs*/ {
+    # NOTE: This is the machine that runs the build -  local from the
+    #       'perspective' of the build script.
+    localSystem = remoteSystem;
+
+    # NOTE: Since this file can't control where the test will be _run_ we don't
+    #       cross-compile _to_ a different system but _from_ a different system
+    crossSystem = pkgs.stdenv.hostPlatform.system;
+  };
+
+  hello1 = remoteCrossPkgs.dockerTools.buildImage {
+    name = "hello1";
+    tag = "latest";
+    contents = remoteCrossPkgs.hello;
+  };
+
+  hello2 = remoteCrossPkgs.dockerTools.buildLayeredImage {
+    name = "hello2";
+    tag = "latest";
+    contents = remoteCrossPkgs.hello;
+  };
+
+in {
+  name = "docker-tools";
+  meta = with pkgs.lib.maintainers; {
+    maintainers = [ roberth ];
+  };
+
+  nodes = {
+    docker = { ... }: {
+      virtualisation = {
+        diskSize = 2048;
+        docker.enable = true;
+      };
+    };
+  };
+
+  testScript = ''
+    docker.wait_for_unit("sockets.target")
+
+    with subtest("Ensure cross compiled buildImage image can run."):
+        docker.succeed(
+            "docker load --input='${hello1}'"
+        )
+        assert "Hello, world!" in docker.succeed(
+            "docker run --rm ${hello1.imageName} hello",
+        )
+        docker.succeed(
+            "docker rmi ${hello1.imageName}",
+        )
+
+    with subtest("Ensure cross compiled buildLayeredImage image can run."):
+        docker.succeed(
+            "docker load --input='${hello2}'"
+        )
+        assert "Hello, world!" in docker.succeed(
+            "docker run --rm ${hello2.imageName} hello",
+        )
+        docker.succeed(
+            "docker rmi ${hello2.imageName}",
+        )
+  '';
+})