CONFIG_DEBUG_STIH418_SBC_ASC0 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Use StiH418 SBC ASC0 UART for low-level debug

configname: CONFIG_DEBUG_STIH418_SBC_ASC0

Kernel low-level debugging port
└─>Use StiH418 SBC ASC0 UART for low-level debug
In linux kernel since version 5.2 (release Date: 2019-07-07)  
Say Y here if you want kernel low-level debugging support
on STiH418 based platforms which has default UART wired
up to SBC ASC0.

If unsure, say N.

depends
CONFIG_ARCH_STI