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

Kernel low-level debugging messages via BCM KONA UART

configname: CONFIG_DEBUG_BCM_KONA_UART

Kernel low-level debugging port
└─>Kernel low-level debugging messages via BCM KONA UART
In linux kernel since version 3.14 (release Date: 2014-03-30)  
Say Y here if you want kernel low-level debugging support
on Broadcom SoC platforms.
This low level debug works for Broadcom
mobile SoCs in the Kona family of chips (e.g. bcm28155,
bcm11351, etc...)