jtag: add support for some probes that are mostly compatible with opendous

This patch adds support for usbprog-jtag and usbvlab that are mostly compatible
to opendous except for IN and OUT endpoints and usb transfer mode.

Change-Id: I44557c2449fe7473295038efa6ae4fc8d80ec7bf
Signed-off-by: Stefan Mahr <stefan.mahr@sphairon.com>
Reviewed-on: http://openocd.zylin.com/687


Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>