default or selected kernelversion does not have config value CONFIG_CRYPTO_SHA512_MB.
Result is shown for kernelversion 6.8.2

SHA512 digest algorithm (x86_64 Multi-Buffer, Experimental)

modulename: sha512-mb.ko

configname: CONFIG_CRYPTO_SHA512_MB

Linux Kernel Configuration
└─>Cryptographic API
└─>SHA512 digest algorithm (x86_64 Multi-Buffer, Experimental)
In linux kernel since version 4.1 (release Date: 2015-06-21)  
SHA-512 secure hash standard (FIPS 180-1/DFIPS 180-2) implemented
using multi-buffer technique. This algorithm computes on
multiple data lanes concurrently with SIMD instructions for
better throughput. It should not be enabled by default but
used when there is significant amount of work to keep the keep
the data lanes filled to get performance benefit. If the data
lanes remain unfilled, a flush operation will be initiated to
process the crypto jobs, adding a slight latency.

source code: