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/misc/mnemonicode/default.nix

@@ -0,0 +1,27 @@
+{ stdenv, lib, fetchFromGitHub }:
+
+stdenv.mkDerivation {
+  pname = "mnemonicode";
+  version = "2015-11-30";
+  src = fetchFromGitHub {
+    owner = "singpolyma";
+    repo = "mnemonicode";
+    rev = "1687fabdf48acf68d4186f219bc20bffe02e8ee0";
+    sha256 = "0kp1jhhqfwfiqg9kx0mbyr4qh4yc4zg4szqk5fbf809nx2pvprm5";
+  };
+  installPhase = ''
+    mkdir -p $out/bin
+    cp mnencode $out/bin
+    cp mndecode $out/bin
+  '';
+  meta = with lib; {
+    description = ''
+      Routines which implement a method for encoding binary data into a sequence
+      of words which can be spoken over the phone, for example, and converted
+      back to data on the other side.
+    '';
+    license = licenses.mit;
+    platforms = platforms.all;
+    maintainers = [ maintainers.cstrahan ];
+  };
+}