CONFIG_RTLWIFI_USB (not configurable)

modulename: rtl_usb.ko

configname: CONFIG_RTLWIFI_USB

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Wireless LAN
└─>Realtek rtlwifi family of devices
└─>RTLWIFI_USB
In linux kernel since version 3.10 (release Date: 2013-06-30)  
source code:
drivers/net/wireless/realtek/rtlwifi/