CONFIG_IOP331_STEPD is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_IOP331_STEPD.
Result is shown for kernelversion 5.4.123

Chip stepping D of the IOP80331 processor or IOP80333

configname: CONFIG_IOP331_STEPD

Linux Kernel Configuration
└─>IOP3xx Implementation Options
└─>Chip stepping D of the IOP80331 processor or IOP80333
In linux kernel since version 2.6.12  
Say Y here if you have StepD of the IOP80331 or IOP8033
based platforms.