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/modules/services/hardware/freefall.nix

@@ -0,0 +1,64 @@
+{ config, lib, pkgs, utils, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.freefall;
+
+in {
+
+  options.services.freefall = {
+
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to protect HP/Dell laptop hard drives (not SSDs) in free fall.
+      '';
+    };
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.freefall;
+      defaultText = literalExpression "pkgs.freefall";
+      description = ''
+        freefall derivation to use.
+      '';
+    };
+
+    devices = mkOption {
+      type = types.listOf types.str;
+      default = [ "/dev/sda" ];
+      description = ''
+        Device paths to all internal spinning hard drives.
+      '';
+    };
+
+  };
+
+  config = let
+
+    mkService = dev:
+      assert dev != "";
+      let dev' = utils.escapeSystemdPath dev; in
+      nameValuePair "freefall-${dev'}" {
+        description = "Free-fall protection for ${dev}";
+        after = [ "${dev'}.device" ];
+        wantedBy = [ "${dev'}.device" ];
+        serviceConfig = {
+          ExecStart = "${cfg.package}/bin/freefall ${dev}";
+          Restart = "on-failure";
+          Type = "forking";
+        };
+      };
+
+  in mkIf cfg.enable {
+
+    environment.systemPackages = [ cfg.package ];
+
+    systemd.services = builtins.listToAttrs (map mkService cfg.devices);
+
+  };
+
+}