CONFIG_ARCH_OMAP2 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

TI OMAP2

modulename: clock24xx.ko

configname: CONFIG_ARCH_OMAP2

OMAP System Type
└─>TI OMAP2
In linux kernel since version 2.6.13 (release Date: 2005-08-28)  
source code:
arch/arm/mach-omap2/clock24xx.c