CONFIG_DEBUG_SOCFPGA_UART0 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Use SOCFPGA UART0 for low-level debug

configname: CONFIG_DEBUG_SOCFPGA_UART0

Kernel low-level debugging port
└─>Use SOCFPGA UART0 for low-level debug
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Say Y here if you want kernel low-level debugging support
on SOCFPGA(Cyclone 5 and Arria 5) based platforms.