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/misc/convfont/default.nix

@@ -0,0 +1,29 @@
+{ lib, stdenv
+, fetchFromGitHub
+}:
+
+stdenv.mkDerivation rec {
+  pname = "convfont";
+  version = "1.0";
+
+  src = fetchFromGitHub {
+    owner = "drdnar";
+    repo = pname;
+    rev = "v20190438";
+    sha256 = "1lj24yq5gj9hxhy1srk73521q95zyqzkws0q4v271hf5wmqaxa2f";
+  };
+
+  makeFlags = [ "CC=${stdenv.cc.targetPrefix}cc" ];
+
+  installPhase = ''
+    install -Dm755 convfont $out/bin/convfont
+  '';
+
+  meta = with lib; {
+    description = "Converts font for use with FontLibC";
+    homepage = "https://github.com/drdnar/convfont";
+    license = licenses.wtfpl;
+    maintainers = with maintainers; [ luc65r ];
+    platforms = platforms.all;
+  };
+}