This updates the USB Gadget stack to Linux-3.15.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Conflicts:
	drivers/usb/core/Makefile

This patch adds support for USB devices. It uses
the Linux Kernel gadget API. Along with this patch
comes driver support for the Freescale (arc) USB OTG
Core and USB Device Firmware Update (DFU)
The serial gadget support is not working at the moment.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>