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

CONFIG_VIOPATH (not configurable)

modulename: viopath.ko

configname: CONFIG_VIOPATH

Linux Kernel Configuration
└─>VIOPATH
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
source code:
/arch/powerpc/platforms/iseries/