rpi-netboot: add kernel modules for debugging

modules/rpi-netboot.nix

@@ -23,6 +23,8 @@
         cp -v ${pkgs.klibc}/lib/klibc/bin.static/nfsmount $out/bin
         cp -v ${pkgs.glibc}/lib/libresolv.so.* $out/lib
       '';
+      # keyboard support for debugging
+      availableKernelModules = [ "usb_storage" "usbhid" ];
     };
 
     tmpOnTmpfs = true;