kernelconfig_penguin
CONFIG_DEBUG_U300_UART is not available for the default architecture x86.
Result is shown for architecture arm

Kernel low-level debugging messages via U300 UART0

configname: CONFIG_DEBUG_U300_UART

Kernel low-level debugging port
└─> Kernel low-level debugging messages via U300 UART0

Say Y here if you want the debug print routines to direct
their output to the uart port on U300 devices.