CONFIG_DEBUG_OMAP2UART3 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Kernel low-level debugging messages via OMAP2 UART3 (n8x0)

configname: CONFIG_DEBUG_OMAP2UART3

Kernel low-level debugging port
└─>Kernel low-level debugging messages via OMAP2 UART3 (n8x0)
In linux kernel since version 3.1 (release Date: 2011-10-24)