removed parts that are included in other modules

dell/xps/15-9560/default.nix

@@ -4,30 +4,22 @@
     ../../../common/gpu/intel/kaby-lake
     ../../../common/pc/laptop
     ./xps-common.nix
+    ../../../common/gpu/nvidia
   ];
 
-# enable opengpl and gpu drivers
   hardware.opengl = {
     enable = true;
     driSupport = true;
     driSupport32Bit = true;
   };
 
-  services.xserver.videoDrivers = ["nvidia"];
-
   hardware.nvidia.modesetting.enable = true;
 
   hardware.nvidia.prime = {
-    offload = {
-      enable = true;
-      enableOffloadCmd = true;  # provides the nvidia-offload command
-    };
-
-# integrated
+  # integrated
     intelBusId = "PCI:0:2:0";
 
-# dedicated
+  # dedicated
     nvidiaBusId = "PCI:1:0:0";
   };
-
 }