USB: gadget: specify vendor/product id with device parameters ...

This introduces the device parameters:

usbgadget.product
usbgadget.vendor
usbgadget.manufacturer
usbgadget.productname

These variables are used to configure the USB vendor id, product id,
manufacturer name and product name.

Previously these were configured with arguments to the usbserial
and dfu command. The parameters are device static, so it's nice to
configure it somewhere in the environment instead of when calling
dfu/usbserial. Also when other gadget drivers are added we do not
have to duplicate the option parsing further.

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

USB: gadget: Update to 3.15 ...

This updates the USB Gadget stack to Linux-3.15.

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

Conflicts:
	drivers/usb/core/Makefile

remove remaining references of CONFIG_BOARDINFO ...

With this all code uses barebox_get_model() and no longer
a compile time generated string.

Also this renames barebox_boardinfo() to barebox_get_model()
since we are going to add the corresponding _set_ function
and 'model' corresponds to the devicetree notion.

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

serial gadget: enable/disable on request ...

- 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>