CONFIG_DEBUG_ASM9260_UART is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Kernel low-level debugging via asm9260 UART

configname: CONFIG_DEBUG_ASM9260_UART

Kernel low-level debugging port
└─>Kernel low-level debugging via asm9260 UART
In linux kernel since version 3.19 (release Date: 2015-02-08)  
Say Y here if you want the debug print routines to direct
their output to an UART or USART port on asm9260 based
machines.

DEBUG_UART_PHYS | DEBUG_UART_VIRT

0x80000000 | 0xf0000000 | UART0
0x80004000 | 0xf0004000 | UART1
0x80008000 | 0xf0008000 | UART2
0x8000c000 | 0xf000c000 | UART3
0x80010000 | 0xf0010000 | UART4
0x80014000 | 0xf0014000 | UART5
0x80018000 | 0xf0018000 | UART6
0x8001c000 | 0xf001c000 | UART7
0x80020000 | 0xf0020000 | UART8
0x80024000 | 0xf0024000 | UART9