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/applications/misc/faircamp/test-wav.nix

@@ -0,0 +1,14 @@
+{ stdenv
+, faircamp
+, ffmpeg
+}:
+
+stdenv.mkDerivation {
+  name = "faircamp-test-wav";
+  meta.timeout = 60;
+  buildCommand = ''
+    mkdir album
+    ${ffmpeg}/bin/ffmpeg -f lavfi -i "sine=frequency=440:duration=1" album/track.wav
+    ${faircamp}/bin/faircamp --build-dir $out
+  '';
+}