CONFIG_DEBUG_SUN9I_UART0 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Kernel low-level debugging messages via sun9i UART0

configname: CONFIG_DEBUG_SUN9I_UART0

Kernel low-level debugging port
└─>Kernel low-level debugging messages via sun9i UART0
In linux kernel since version 3.19 (release Date: 2015-02-08)  
Say Y here if you want kernel low-level debugging support
on Allwinner A80 based platforms on the UART0.