CONFIG_ARCH_S5P6440 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_ARCH_S5P6440.
Result is shown for kernelversion 5.4.229

Samsung S5P6440

configname: CONFIG_ARCH_S5P6440

ARM system type
└─>Samsung S5P6440
In linux kernel since version 2.6.34 (release Date: 2010-05-16)  
Samsung S5P6440 CPU based systems