This patchs adds a new access driver for the existing
USB-Blaster interface driver.

This interface (as it is build-in on the sockit development
board) is composed of a Cypress EZ-USB plus a CPLD.

The Cypress chip as an embedded 8051 microcontroller.
When it's powered up, the firmware is downloaded to the
chip then the device is disconnected and reconnected with
the new firmware.

The USB-Blaster II protocol is almost identicial to
the old one. The only difference is that you need to
send a 0x5F before read TDO back. This command
seems to copy TDO buffer datas to the endpoint buffer.

Driver will be auto enabled if libusb-1.0 is detected.

Change-Id: I562a720a68cb4dcabeab791947d5d38776cb70fa
Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
Reviewed-on: http://openocd.zylin.com/1791


Tested-by: jenkins
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>