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

Support Eicon DIVA Server cards

modulename: divadidd.ko

configname: CONFIG_ISDN_DIVAS

Linux Kernel Configuration
└─>Device Drivers
└─>ISDN support
└─>CAPI 2.0 subsystem
└─>Active Eicon DIVA Server cards
└─>Support Eicon DIVA Server cards
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Say Y here if you have an Eicon Networks DIVA Server PCI ISDN card.
In order to use this card, additional firmware is necessary, which
has to be downloaded into the card using the divactrl utility.

source code: