interface: Add XDS100v3 support.

XDS100v3 is software compatible with the XDS100v2, but has a
different usb pid. This commit adds `xds100v3.cfg` that sources
the v2 one and changes the usb pid.

Change-Id: Ie29d325e8992d2de2f97d70862beeb63932ffa80
Signed-off-by: Remco Bloemen <openocd-gerrit@xn--2-umb.com>
Reviewed-on: http://openocd.zylin.com/3632
Tested-by: jenkins
Reviewed-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

tcl/interface/ftdi/xds100v3.cfg

@@ -0,0 +1,11 @@
+#
+# Texas Instruments XDS100 ver 3.0
+#
+# http://processors.wiki.ti.com/index.php/XDS100
+#
+
+# Version 3.0 is the same as 2.0 as far as OpenOCD is concerned
+source [find interface/ftdi/xds100v2.cfg]
+
+# The USB ids are different.
+ftdi_vid_pid 0x0403 0xa6d1