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>

pkgs/build-support/build-setupcfg/default.nix

@@ -0,0 +1,25 @@
+# Build a python package from info made available by setupcfg2nix.
+#
+# * src: The source of the package.
+# * info: The package information generated by setupcfg2nix.
+# * meta: Standard nixpkgs metadata.
+# * application: Whether this package is a python library or an
+#   application which happens to be written in python.
+# * doCheck: Whether to run the test suites.
+pythonPackages:
+{ src, info, meta ? {}, application ? false, doCheck ? true }: let
+  build = if application
+    then pythonPackages.buildPythonApplication
+  else pythonPackages.buildPythonPackage;
+in build {
+  inherit (info) pname version;
+
+  inherit src meta doCheck;
+
+  nativeBuildInputs = map (p: pythonPackages.${p}) (
+    (info.setup_requires or []) ++
+    (if doCheck then (info.tests_require or []) else []));
+
+  propagatedBuildInputs = map (p: pythonPackages.${p})
+    (info.install_requires or []);
+}