Introduce general-intel.nix for defaults with Intel CPU

The x1xx series relies on a AMD CPU, but all other (currently supported)
ThinkPads use an Intel CPU, so `general-intel.nix` is responsible
for all Intel defaults.

lenovo/thinkpad/general-intel.nix

@@ -0,0 +1,6 @@
+{ ... }:
+
+{
+  boot.kernelModules = mkDefault [ "kvm-intel" ];
+  services.xserver.videoDrivers = [ "intel" ];
+}

lenovo/thinkpad/t410.nix

@@ -1,7 +1,7 @@
 { config, pkgs, ... }:
 
 {
-  imports = [ ./general.nix ];
+  imports = [ ./general-intel.nix ];
 
   boot = {
     kernelParams = [

lenovo/thinkpad/t440p.nix

@@ -1,12 +1,12 @@
 { config, pkgs, ... }:
 
 {
-  imports = [ ./general.nix ];
+  imports = [ ./general-intel.nix ];
 
   boot = {
     extraModprobeConfig = ''
       options bbswitch use_acpi_to_detect_card_state=1
     '';
-    kernelModules = [ "kvm-intel" "tpm-rng" ];
+    kernelModules = [ "tpm-rng" ];
   };
 }

lenovo/thinkpad/t460s.nix

@@ -3,7 +3,7 @@
 {
   imports =
     [ ../lib/kernel-version.nix
-      ./general.nix
+      ./general-intel.nix
     ];
 
   ## BEGIN from generated hardware-configuration

lenovo/thinkpad/x220i-tablet.nix

@@ -1,7 +1,7 @@
 { config, pkgs, ... }:
 
 {
-  imports = [ ./general.nix ];
+  imports = [ ./general-intel.nix ];
 
   # TPM chip countains a RNG
   security.rngd.enable = true;

lenovo/thinkpad/x250.nix

@@ -1,8 +1,5 @@
 { config, pkgs, ... }:
 
 {
-  imports = [ ./general.nix ];
-
-   # modesetting driver leads to freezes with newer kernel at the moment (> 4.4)
-   services.xserver.videoDrivers = [ "intel" ];
+  imports = [ ./general-intel.nix ];
 }