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/graphics/vengi-tools/test-voxconvert-all-formats.nix

@@ -0,0 +1,15 @@
+{ stdenv
+, vengi-tools
+}:
+
+stdenv.mkDerivation {
+  name = "vengi-tools-test-voxconvert-all-formats";
+  meta.timeout = 10;
+  buildCommand = ''
+    mkdir $out
+    for format in vox qef qbt qb vxm vxr binvox gox cub vxl csv; do
+      echo Testing $format export
+      ${vengi-tools}/bin/vengi-voxconvert --input ${vengi-tools}/share/vengi-voxedit/chr_knight.qb --output $out/chr_knight.$format
+    done
+  '';
+}