CONFIG_MACH_SMDK6442 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_SMDK6442.
Result is shown for kernelversion 5.4.69

SMDK6442

modulename: mach-smdk6442.ko

configname: CONFIG_MACH_SMDK6442

Linux Kernel Configuration
└─>SMDK6442
In linux kernel since version 2.6.34 (release Date: 2010-05-16)  
Machine support for Samsung SMDK6442

source code: