CONFIG_S3C_DEV_I2C1 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_S3C_DEV_I2C1 (not configurable)

modulename: dev-i2c1.ko

configname: CONFIG_S3C_DEV_I2C1

Linux Kernel Configuration
└─>S3C_DEV_I2C1
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
Compile in platform device definitions for I2C channel 1

source code:
arch/arm/plat-samsung/dev-i2c1.c
depends
CONFIG_PLAT_SAMSUNG |
| CONFIG_SAMSUNG_ATAGS