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

CONFIG_ARCH_SUPPORTS_BIG_ENDIAN (not configurable)

configname: CONFIG_ARCH_SUPPORTS_BIG_ENDIAN

Linux Kernel Configuration
└─>ARCH_SUPPORTS_BIG_ENDIAN
In linux kernel since version 2.6.12  
This option specifies the architecture can support big endian
operation.