default or selected kernelversion does not have config value CONFIG_ATM_FORE200E_SBA_FW.
Result is shown for kernelversion 5.4.123

Pathname of user-supplied binary firmware

configname: CONFIG_ATM_FORE200E_SBA_FW

Linux Kernel Configuration
└─>Networking support
└─>ATM drivers
└─>Pathname of user-supplied binary firmware
In linux kernel since version 2.6.12  
This defines the pathname of an alternative SBA-200E binary
firmware image supplied by the user. This pathname may be
absolute or relative to the drivers/atm directory.

The driver comes with an adequate firmware image, so normal users do
not have to supply an alternative one. They just say Y to "Use
default SBA-200E firmware", above.