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

Thunder MAC interface driver (BGX)

modulename: thunder_bgx.ko


Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>PCI support
└─>Thunder MAC interface driver (BGX)
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This driver supports programming and controlling of MAC
interface from NIC physical function driver.

source code: