CONFIG_HAVE_ARCH_PFN_VALID is not available for the selected architecture x86.
Result is shown for architecture arm64

CONFIG_HAVE_ARCH_PFN_VALID (not configurable)

configname: CONFIG_HAVE_ARCH_PFN_VALID

Linux Kernel Configuration
└─>Kernel Features
└─>HAVE_ARCH_PFN_VALID
In linux kernel since version 3 (release Date: 2011-07-21)