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

Software async multi-buffer crypto daemon

modulename: mcryptd.ko

configname: CONFIG_CRYPTO_MCRYPTD

Linux Kernel Configuration
└─>Cryptographic API
└─>Software async multi-buffer crypto daemon
In linux kernel since version 3.18 (release Date: 2014-12-07)  
This is a generic software asynchronous crypto daemon that
provides the kernel thread to assist multi-buffer crypto
algorithms for submitting jobs and flushing jobs in multi-buffer
crypto algorithms. Multi-buffer crypto algorithms are executed
in the context of this kernel thread and drivers can post
their crypto request asynchronously to be processed by this daemon.

source code: