CONFIG_MACH_SMDK2413 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

SMDK2413

modulename: mach-smdk2413.ko

configname: CONFIG_MACH_SMDK2413

Linux Kernel Configuration
└─>Samsung S3C24XX SoCs Support
└─>SMDK2413
In linux kernel since version 2.6.18 (release Date: 2006-09-19)  
Say Y here if you are using an SMDK2413