CONFIG_S3C_DEV_FB is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_S3C_DEV_FB (not configurable)

configname: CONFIG_S3C_DEV_FB

Linux Kernel Configuration
└─>Samsung Common options
└─>S3C_DEV_FB
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
Compile in platform device definition for framebuffer