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>

nixos/doc/manual/development/activation-script.section.md

@@ -0,0 +1,72 @@
+# Activation script {#sec-activation-script}
+
+The activation script is a bash script called to activate the new
+configuration which resides in a NixOS system in `$out/activate`. Since its
+contents depend on your system configuration, the contents may differ.
+This chapter explains how the script works in general and some common NixOS
+snippets. Please be aware that the script is executed on every boot and system
+switch, so tasks that can be performed in other places should be performed
+there (for example letting a directory of a service be created by systemd using
+mechanisms like `StateDirectory`, `CacheDirectory`, ... or if that's not
+possible using `preStart` of the service).
+
+Activation scripts are defined as snippets using
+[](#opt-system.activationScripts). They can either be a simple multiline string
+or an attribute set that can depend on other snippets. The builder for the
+activation script will take these dependencies into account and order the
+snippets accordingly. As a simple example:
+
+```nix
+system.activationScripts.my-activation-script = {
+  deps = [ "etc" ];
+  # supportsDryActivation = true;
+  text = ''
+    echo "Hallo i bims"
+  '';
+};
+```
+
+This example creates an activation script snippet that is run after the `etc`
+snippet. The special variable `supportsDryActivation` can be set so the snippet
+is also run when `nixos-rebuild dry-activate` is run. To differentiate between
+real and dry activation, the `$NIXOS_ACTION` environment variable can be
+read which is set to `dry-activate` when a dry activation is done.
+
+An activation script can write to special files instructing
+`switch-to-configuration` to restart/reload units. The script will take these
+requests into account and will incorperate the unit configuration as described
+above. This means that the activation script will "fake" a modified unit file
+and `switch-to-configuration` will act accordingly. By doing so, configuration
+like [systemd.services.\<name\>.restartIfChanged](#opt-systemd.services) is
+respected. Since the activation script is run **after** services are already
+stopped, [systemd.services.\<name\>.stopIfChanged](#opt-systemd.services)
+cannot be taken into account anymore and the unit is always restarted instead
+of being stopped and started afterwards.
+
+The files that can be written to are `/run/nixos/activation-restart-list` and
+`/run/nixos/activation-reload-list` with their respective counterparts for
+dry activation being `/run/nixos/dry-activation-restart-list` and
+`/run/nixos/dry-activation-reload-list`. Those files can contain
+newline-separated lists of unit names where duplicates are being ignored. These
+files are not create automatically and activation scripts must take the
+possiblility into account that they have to create them first.
+
+## NixOS snippets {#sec-activation-script-nixos-snippets}
+
+There are some snippets NixOS enables by default because disabling them would
+most likely break you system. This section lists a few of them and what they
+do:
+
+- `binsh` creates `/bin/sh` which points to the runtime shell
+- `etc` sets up the contents of `/etc`, this includes systemd units and
+  excludes `/etc/passwd`, `/etc/group`, and `/etc/shadow` (which are managed by
+  the `users` snippet)
+- `hostname` sets the system's hostname in the kernel (not in `/etc`)
+- `modprobe` sets the path to the `modprobe` binary for module auto-loading
+- `nix` prepares the nix store and adds a default initial channel
+- `specialfs` is responsible for mounting filesystems like `/proc` and `sys`
+- `users` creates and removes users and groups by managing `/etc/passwd`,
+  `/etc/group` and `/etc/shadow`. This also creates home directories
+- `usrbinenv` creates `/usr/bin/env`
+- `var` creates some directories in `/var` that are not service-specific
+- `wrappers` creates setuid wrappers like `ping` and `sudo`