chn: xserver drivers to per host basis

hosts/nixbook/default.nix

@@ -21,6 +21,5 @@
     steam
   ];
 
-  # explicitly override videoDrivers (nvidia doesnt like us on nixbook )
-  services.xserver.videoDrivers = lib.mkForce [ "intel" ];
+  services.xserver.videoDrivers = [ "intel" ];
 }