treewide: drop hardware.amdgpu.amdvlk option

This is now provided in nixpkgs (see https://github.com/NixOS/nixpkgs/pull/318175).

lenovo/legion/16achg6/nvidia/default.nix

@@ -5,9 +5,6 @@
   services.xserver.videoDrivers = [ "nvidia" ];
   hardware = {
     nvidia.prime.offload.enable = false;
-    amdgpu = {
-      amdvlk = false;
-      opencl = false;
-    };
+    amdgpu.opencl = false;
   };
-}
+}