CONFIG_ARCH_MX2 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_ARCH_MX2.
Result is shown for kernelversion 6.2.5

MX2-based

configname: CONFIG_ARCH_MX2

Freescale CPU family:
└─>MX2-based
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
This enables support for systems based on the Freescale i.MX2 family