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

Hardware multithreading

configname: CONFIG_HMT

Linux Kernel Configuration
└─>Hardware multithreading
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
This option enables hardware multithreading on RS64 cpus.
pSeries systems p620 and p660 have such a cpu type.

depends
CONFIG_BROKEN
CONFIG_PPC_PSERIES
CONFIG_SMP