CONFIG_ARCH_OMAP15XX is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
OMAP15xx Based System
modulename: gpio15xx.ko
configname: CONFIG_ARCH_OMAP15XX
Linux Kernel Configuration
└─>TI OMAP1
└─>TI OMAP1 specific features
└─>OMAP15xx Based System