CONFIG_DEBUG_OMAP2PLUS_UART is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Kernel low-level debugging messages via OMAP2PLUS UART

configname: CONFIG_DEBUG_OMAP2PLUS_UART

Kernel low-level debugging port
└─>Kernel low-level debugging messages via OMAP2PLUS UART
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Say Y here if you want kernel low-level debugging support
on OMAP2PLUS based platforms.