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

CONFIG_ARCH_OMAP (not configurable)

modulename: gpio-omap.ko

configname: CONFIG_ARCH_OMAP

Linux Kernel Configuration
└─>ARCH_OMAP
In linux kernel since version 2.6.12  
source code:
drivers/gpio/gpio-omap.c