CONFIG_DEBUG_MT6589_UART0 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Mediatek mt6589 UART0

configname: CONFIG_DEBUG_MT6589_UART0

Kernel low-level debugging port
└─>Mediatek mt6589 UART0
In linux kernel since version 3.18 (release Date: 2014-12-07)  
Say Y here if you want kernel low-level debugging support
for Mediatek mt6589 based platforms on UART0.