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/hardware/video/displaylink.nix

@@ -0,0 +1,76 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  enabled = elem "displaylink" config.services.xserver.videoDrivers;
+
+  evdi = config.boot.kernelPackages.evdi;
+
+  displaylink = pkgs.displaylink.override {
+    inherit evdi;
+  };
+
+in
+
+{
+
+  config = mkIf enabled {
+
+    boot.extraModulePackages = [ evdi ];
+    boot.kernelModules = [ "evdi" ];
+
+    environment.etc."X11/xorg.conf.d/40-displaylink.conf".text = ''
+      Section "OutputClass"
+        Identifier  "DisplayLink"
+        MatchDriver "evdi"
+        Driver      "modesetting"
+        Option      "AccelMethod" "none"
+      EndSection
+    '';
+
+    # make the device available
+    services.xserver.displayManager.sessionCommands = ''
+      ${lib.getBin pkgs.xorg.xrandr}/bin/xrandr --setprovideroutputsource 1 0
+    '';
+
+    # Those are taken from displaylink-installer.sh and from Arch Linux AUR package.
+
+    services.udev.packages = [ displaylink ];
+
+    powerManagement.powerDownCommands = ''
+      #flush any bytes in pipe
+      while read -n 1 -t 1 SUSPEND_RESULT < /tmp/PmMessagesPort_out; do : ; done;
+
+      #suspend DisplayLinkManager
+      echo "S" > /tmp/PmMessagesPort_in
+
+      #wait until suspend of DisplayLinkManager finish
+      if [ -f /tmp/PmMessagesPort_out ]; then
+        #wait until suspend of DisplayLinkManager finish
+        read -n 1 -t 10 SUSPEND_RESULT < /tmp/PmMessagesPort_out
+      fi
+    '';
+
+    powerManagement.resumeCommands = ''
+      #resume DisplayLinkManager
+      echo "R" > /tmp/PmMessagesPort_in
+    '';
+
+    systemd.services.dlm = {
+      description = "DisplayLink Manager Service";
+      after = [ "display-manager.service" ];
+      conflicts = [ "getty@tty7.service" ];
+
+      serviceConfig = {
+        ExecStart = "${displaylink}/bin/DisplayLinkManager";
+        Restart = "always";
+        RestartSec = 5;
+        LogsDirectory = "displaylink";
+      };
+    };
+
+  };
+
+}