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/servers/web-apps/discourse/auto_generated_path.patch

@@ -0,0 +1,13 @@
+diff --git a/lib/plugin/instance.rb b/lib/plugin/instance.rb
+index 8482ff0210..826d111d65 100644
+--- a/lib/plugin/instance.rb
++++ b/lib/plugin/instance.rb
+@@ -455,7 +455,7 @@ class Plugin::Instance
+   end
+ 
+   def auto_generated_path
+-    File.dirname(path) << "/auto_generated"
++    "#{Rails.root}/public/assets/auto_generated_plugin_assets/#{name}"
+   end
+ 
+   def after_initialize(&block)