CONFIG_PPC_HAVE_KUEP is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

CONFIG_PPC_HAVE_KUEP (not configurable)

configname: CONFIG_PPC_HAVE_KUEP

Linux Kernel Configuration
└─>Processor support
└─>PPC_HAVE_KUEP
In linux kernel since version 5.1 (release Date: 2019-05-05)  
is depended by
CONFIG_PPC_BOOK3S_64