cudaPackages.cuda-samples: set `meta.platforms`

pkgs/development/cuda-modules/cuda-samples/generic.nix

···
     description = "Samples for CUDA Developers which demonstrates features in CUDA Toolkit";
     # CUDA itself is proprietary, but these sample apps are not.
     license = lib.licenses.bsd3;
+    platforms = [ "x86_64-linux" ];
     maintainers = with lib.maintainers; [ obsidian-systems-maintenance ] ++ lib.teams.cuda.members;
   };
 })