CONFIG_MACH_SMDK6442 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
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