CONFIG_ARCH_OMAP34XX is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

OMAP34xx Based System

configname: CONFIG_ARCH_OMAP34XX

Linux Kernel Configuration
└─>OMAP34xx Based System
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  

is selected by
CONFIG_ARCH_OMAP3430