default or selected kernelversion does not have config value CONFIG_DLCI_COUNT.
Result is shown for kernelversion 5.4.123

Max open DLCI

configname: CONFIG_DLCI_COUNT

Linux Kernel Configuration
└─>Networking support
└─>Wan interfaces
└─>Max open DLCI
In linux kernel since version 2.6.12  
Maximal number of logical point-to-point frame relay connections
(the identifiers of which are called DCLIs) that the driver can
handle.

The default is probably fine.