CONFIG_S3C_DEV_USB_HOST is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_S3C_DEV_USB_HOST (not configurable)

modulename: dev-usb.ko

configname: CONFIG_S3C_DEV_USB_HOST

Linux Kernel Configuration
└─>S3C_DEV_USB_HOST
In linux kernel since version 2.6.31 (release Date: 2009-09-09)  
Compile in platform device definition for USB host.

source code:
arch/arm/plat-s3c/dev-usb.c