Move libinput to ThinkPad-specific config

hosts/desktop.nix

@@ -7,10 +7,6 @@ in
   services = {
    xserver = {
       enable = true;
-      libinput = {
-        enable = true;
-        touchpad.tapping = true;
-      };
       xkbOptions = "caps:escape";
       displayManager = {
         lightdm = {

hosts/thinkpads/default.nix

@@ -17,4 +17,9 @@
   # Use X11 caps lock to escape remap in TTY
   console.useXkbConfig = true;
   services.xserver.xkbOptions = "caps:escape";
+
+  services.xserver.libinput = {
+    enable = true;
+    touchpad.tapping = true;
+  };
 }