default or selected kernelversion does not have config value CONFIG_CRYPTO_SHA256_X86_64.
Result is shown for kernelversion 6.16-rc7

CONFIG_CRYPTO_SHA256_X86_64 (not configurable)

modulename: sha256-x86_64.ko

configname: CONFIG_CRYPTO_SHA256_X86_64

Linux Kernel Configuration
└─>CRYPTO_SHA256_X86_64
In linux kernel since version 6.1.145 (release Date: 2025-07-14)  
source code:
/arch/x86/lib/crypto/

depends
CONFIG_64BIT |
| CONFIG_X86 or  NOT CONFIG_KMSAN