CONFIG_MIPS_MT_SMP is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

MIPS MT SMP support (1 TC on each available VPE)

modulename: smp-mt.ko

configname: CONFIG_MIPS_MT_SMP

Linux Kernel Configuration
└─>Kernel type
└─>MIPS MT SMP support (1 TC on each available VPE)
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
This is a kernel model which is known as SMVP. This is supported
on cores with the MT ASE and uses the available VPEs to implement
virtual processors which supports SMP. This is equivalent to the
Intel Hyperthreading feature. For further information go to
<http://www.imgtec.com/mips/mips-multithreading.asp>.

source code: