CONFIG_DEBUG_OMAP2UART3 is not available for the selected architecture x86.
Result is shown for architecture arm

OMAP2 UART3 (n8x0)

configname: CONFIG_DEBUG_OMAP2UART3

Low-level debug console UART
└─>OMAP2 UART3 (n8x0)
In linux kernel since version 3.1 (release Date: 2011-10-24)
selects
CONFIG_DEBUG_OMAP2PLUS_UART
CONFIG_DEBUG_UART_8250

depends
 or CONFIG_ARCH_OMAP2PLUS