gnuradioPackages.grnet: remove

Cannot be used anymore by any modern GR version.

Author: doronbehar

pkgs/development/gnuradio-modules/grnet/default.nix

@@ -39,6 +39,4 @@ in {
 
   fosphor = callPackage ../development/gnuradio-modules/fosphor/default.nix { };
 
-  grnet = callPackage ../development/gnuradio-modules/grnet/default.nix { };
-
 })