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

CONFIG_ARCH_SUPPORTS_TRUSTED_FOUNDATIONS (not configurable)

configname: CONFIG_ARCH_SUPPORTS_TRUSTED_FOUNDATIONS

Linux Kernel Configuration
└─>ARCH_SUPPORTS_TRUSTED_FOUNDATIONS
In linux kernel since version 3.14 (release Date: 2014-03-30)