cfg: add default pid/vid pair to beaglebone board cfg.

cfg: add default pid/vid pair to beaglebone board cfg.

The newer versions of BeagleBone boards use the default vid/pid
pair for FT2232 debugging.  Please see the following README:
http://beagleboard.org/static/beaglebone/latest/README.htm
On revision A3/A4 boards, the VID/PID were chosen to match the
 TI XDS100v2 (0x0403/0xA6D0). On A5 and newer revisions when we've
 given the authors of CCS the chance to update their software, the
generic FTDI VID/PID (0x0403/0x6010) will be used to simplify
installation of drivers for systems already having those drivers.

Change-Id: I44228eb2029162f23d084eb05bcfef39e615668d
Signed-off-by: Bill Traynor <wmat@alphatroop.com>
Reviewed-on: http://openocd.zylin.com/619
Tested-by: jenkins
Reviewed-by: Peter Stuge <peter@stuge.se>