Compiling the Kernel with Composite Gadget support

On kernel source directory:
#make menuconfig
Select:
Device Drivers --->
... USB support --->
...... USB Gadget Support --->
......... [M] Composite Gadget Support
......... [M] Ethernet Gadget (with CDC Ether support)
............ [ ] RNDIS support (EXPERIMENTAL)
......... [M] File-backed Storage Gadget

In the first version the Composite Gadget has support for file storage and ether only.
Select RNDIS support to use your ether gadget in Windows OS for example.

After this
#make modules && make modules_install