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/virtualisation/xe-guest-utilities.nix

@@ -0,0 +1,52 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.xe-guest-utilities;
+in {
+  options = {
+    services.xe-guest-utilities = {
+      enable = mkEnableOption "the Xen guest utilities daemon";
+    };
+  };
+  config = mkIf cfg.enable {
+    services.udev.packages = [ pkgs.xe-guest-utilities ];
+    systemd.tmpfiles.rules = [ "d /run/xenstored 0755 - - -" ];
+
+    systemd.services.xe-daemon = {
+      description = "xen daemon file";
+      wantedBy    = [ "multi-user.target" ];
+      after = [ "xe-linux-distribution.service" ];
+      requires = [ "proc-xen.mount" ];
+      path = [ pkgs.coreutils pkgs.iproute2 ];
+      serviceConfig = {
+        PIDFile = "/run/xe-daemon.pid";
+        ExecStart = "${pkgs.xe-guest-utilities}/bin/xe-daemon -p /run/xe-daemon.pid";
+        ExecStop = "${pkgs.procps}/bin/pkill -TERM -F /run/xe-daemon.pid";
+      };
+    };
+
+    systemd.services.xe-linux-distribution = {
+      description = "xen linux distribution service";
+      wantedBy    = [ "multi-user.target" ];
+      before = [ "xend.service" ];
+      path = [ pkgs.xe-guest-utilities pkgs.coreutils pkgs.gawk pkgs.gnused ];
+      serviceConfig = {
+        Type = "simple";
+        RemainAfterExit = "yes";
+        ExecStart = "${pkgs.xe-guest-utilities}/bin/xe-linux-distribution /var/cache/xe-linux-distribution";
+      };
+    };
+
+    systemd.mounts = [
+      { description = "Mount /proc/xen files";
+        what = "xenfs";
+        where = "/proc/xen";
+        type = "xenfs";
+        unitConfig = {
+          ConditionPathExists = "/proc/xen";
+          RefuseManualStop = "true";
+        };
+      }
+    ];
+  };
+}