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

IBM Virtual Accelerator Switchboard (VAS)

modulename: vas.ko

configname: CONFIG_PPC_VAS

Linux Kernel Configuration
└─>IBM Virtual Accelerator Switchboard (VAS)
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables support for IBM Virtual Accelerator Switchboard (VAS).

VAS allows accelerators in co-processors like NX-GZIP and NX-842
to be accessible to kernel subsystems and user processes.

VAS adapters are found in POWER9 based systems.

If unsure, say N.

source code: