This updates the USB Gadget stack to Linux-3.15.

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

Conflicts:
	drivers/usb/core/Makefile

- add a usbserial command to enable/disable the serial gadget
- allow dfu and usbserial to cohexist in the same barebox
- add a timeout in u_serial so that we don't get locked if the user
enable usbserial from a UART console but doesn't consume the data
on the usbserial port created on the PC
- remove debug or verbose printf
- tested on i.MX25 & i.MX35 & usb-a926x

Signed-off-by: Eric Bénard <eric@eukrea.com>
Tested-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

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>