CONFIG_ARM64_SME is not available for the default architecture x86.
Result is shown for architecture arm64
default or selected kernelversion does not have config value CONFIG_ARM64_SME.
Result is shown for kernelversion 6.0-rc7

ARM Scalable Matrix Extension support

configname: CONFIG_ARM64_SME

Linux Kernel Configuration
└─> Kernel Features
└─> ARM Scalable Matrix Extension support

The Scalable Matrix Extension (SME) is an extension to the AArch64
execution state which utilises a substantial subset of the SVE
instruction set, together with the addition of new architectural
register state capable of holding two dimensional matrix tiles to
enable various matrix operations.