CONFIG_ARCH_VEXPRESS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
ARM Ltd. Versatile Express family
configname: CONFIG_ARCH_VEXPRESS
ARM system type
└─>ARM Ltd. Versatile Express family
In linux kernel since version 2.6.35 (release Date: 2010-08-01)
This enables support for the ARM Ltd Versatile Express boards.