Segregate lenovo/ subdir into thinkpad and ideapad directories

There are several significant differences between ThinkPads and the
other Lenovo models, so this structure must be more precise

lenovo/thinkpad/x140e.nix

@@ -0,0 +1,22 @@
+{ config, lib, pkgs, ... }:
+
+{
+  imports = [ ./general.nix ];
+
+  boot = {
+    # wireless
+    kernelModules = [ "kvm-amd" "wl" ];
+    extraModulePackages = [ config.boot.kernelPackages.broadcom_sta ];
+
+    # audio device
+    extraModprobeConfig = ''
+      options snd_hda_intel enable=0,1
+    '';
+  };
+
+  # video card
+  services.xserver.videoDrivers = ["ati"];
+
+  # media keys
+  sound.enableMediaKeys = true;
+}