CONFIG_ARCH_VEXPRESS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

ARMv8 software model (Versatile Express)

modulename: clk-vexpress.ko

configname: CONFIG_ARCH_VEXPRESS

Linux Kernel Configuration
└─>Platform selection
└─>ARMv8 software model (Versatile Express)
In linux kernel since version 2.6.35 (release Date: 2010-08-01)  
This enables support for the ARMv8 software model (Versatile
Express).