CONFIG_THUNDER_NIC_VF is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

Thunder Virtual function driver

modulename: nicvf.ko

configname: CONFIG_THUNDER_NIC_VF

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>PCI support
└─>Thunder Virtual function driver
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This driver supports Thunder's NIC virtual function

source code:
drivers/net/ethernet/cavium/thunder/