CONFIG_DEBUG_OMAP4UART3 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

OMAP4/5 UART3 (omap4 blaze, panda, omap5 sevm)

configname: CONFIG_DEBUG_OMAP4UART3

Low-level debug console UART
└─>OMAP4/5 UART3 (omap4 blaze, panda, omap5 sevm)
In linux kernel since version 3.1 (release Date: 2011-10-24)  

depends
 or CONFIG_ARCH_OMAP2PLUS