USB: Add support for Olimex arm-usb-ocd JTAG interface serial port

This patch adds support for the serial port on Olimex arm-usb-ocd
JTAG interface.

The device appears as two serial ports, but the first one is reserved
for the JTAG interface. The JTAG interface can be used with OpenOCD
from userspace. For more information, please see:

http://openocd.berlios.de/web/
http://www.olimex.com/dev/arm-usb-ocd.html

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>