CONFIG_S3C_DEV_HSMMC is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_S3C_DEV_HSMMC (not configurable)

modulename: dev-hsmmc.ko

configname: CONFIG_S3C_DEV_HSMMC

Linux Kernel Configuration
└─>S3C_DEV_HSMMC
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
Compile in platform device definitions for HSMMC code

source code:
depends
CONFIG_PLAT_S3C

is depended by
CONFIG_MACH_SMDK2443