Include configuration with CDC ECM (Ethernet)

configname: CONFIG_USB_FUNCTIONFS_ETH

Linux Kernel Configuration
└─>Device Drivers
└─>USB support
└─>USB Gadget Support
└─>USB Gadget precomposed configurations
└─>Include configuration with CDC ECM (Ethernet)
In linux kernel since version 2.6.35 (release Date: 2010-08-01)  
Include a configuration with CDC ECM function (Ethernet) and the
Function Filesystem.