default or selected kernelversion does not have config value CONFIG_DGNC.
Result is shown for kernelversion 6.9.9

Digi Neo and Classic PCI Products

modulename: dgnc.ko

configname: CONFIG_DGNC

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Digi Neo and Classic PCI Products
In linux kernel since version 3.12 (release Date: 2013-11-03)  
Driver for the Digi International Neo and Classic PCI based product line.

source code:
drivers/staging/dgnc/