CONFIG_TEGRA_DEBUG_UART_AUTO_SCRATCH is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_TEGRA_DEBUG_UART_AUTO_SCRATCH.
Result is shown for kernelversion 5.15.31

Via UART scratch register


Automatic low-level debug console UART
└─>Via UART scratch register
In linux kernel since version 3.5 (release Date: 2012-07-21)  
Automatically determines which UART to use for low-level debug based
on the UART scratch register value. Some bootloaders put ASCII 'D'
in this register when they initialize their own console UART output.
Using this option allows the kernel to automatically pick the same