CONFIG_ARCH_VEXPRESS is not available for the default architecture x86.
Result is shown for architecture arm

ARM Ltd. Versatile Express family

modulename: v2m.ko

Linux Kernel Configuration
└─> ARM Ltd. Versatile Express family

This option enables support for systems using Cortex processor based
ARM core and logic (FPGA) tiles on the Versatile Express motherboard,
for example:

- CoreTile Express A5x2 (V2P-CA5s)
- CoreTile Express A9x4 (V2P-CA9)
- CoreTile Express A15x2 (V2P-CA15)
- LogicTile Express 13MG (V2F-2XV6) with A5, A7, A9 or A15 SMMs
(Soft Macrocell Models)
- Versatile Express RTSMs (Models)

You must boot using a Flattened Device Tree in order to use these
platforms. The traditional (ATAGs) boot method is not usable on
these boards with this option.

source code: