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

NetX Ethernet support

modulename: netx-eth.ko

configname: CONFIG_NET_NETX

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>NetX Ethernet support
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This is support for the Hilscher netX builtin Ethernet ports

To compile this driver as a module, choose M here. The module
will be called netx-eth.

source code: