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/tools/text/cconv/default.nix

@@ -0,0 +1,24 @@
+{ lib, stdenv, fetchFromGitHub, autoreconfHook, libiconv }:
+
+stdenv.mkDerivation rec {
+  pname = "cconv";
+  version = "0.6.3";
+
+  src = fetchFromGitHub {
+    owner = "xiaoyjy";
+    repo = "cconv";
+    rev = "v${version}";
+    sha256 = "RAFl/+I+usUfeG/l17F3ltThK7G4+TekyQGwzQIgeH8=";
+  };
+
+  nativeBuildInputs = [ autoreconfHook ];
+  buildInputs = [ libiconv ];
+
+  meta = with lib; {
+    description = "A iconv based simplified-traditional chinese conversion tool";
+    homepage = "https://github.com/xiaoyjy/cconv";
+    license = licenses.mit;
+    platforms = platforms.all;
+    maintainers = [ maintainers.redfish64 ];
+  };
+}