CONFIG_DEBUG_RV1108_UART2 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Kernel low-level debugging messages via Rockchip RV1108 UART2

configname: CONFIG_DEBUG_RV1108_UART2

Kernel low-level debugging port
└─>Kernel low-level debugging messages via Rockchip RV1108 UART2
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Say Y here if you want kernel low-level debugging support
on Rockchip RV1108 based platforms.