default or selected kernelversion does not have config value CONFIG_BENET.
Result is shown for kernelversion 5.14.15

ServerEngines 10Gb NIC - BladeEngine

modulename: benet.ko

configname: CONFIG_BENET

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>ServerEngines 10Gb NIC - BladeEngine
In linux kernel since version 2.6.29.1 (release Date: 2009-04-02)  
This driver implements the NIC functionality for ServerEngines
10Gb network adapter BladeEngine (EC 3210).

source code:
drivers/staging/benet/
selects
CONFIG_INET_LRO