digilent_jtag_smt2_nc: add support

The Digilent SMT2 NC is nominally the connector-less version of the
SMT2. But neither the SMT2 configuration nor the HS3 configuration work
for on the Xilinx KCU105 board where the SMT2 NC is used.

Change-Id: Ieb27cbc6d8b0f9c64ef778e4e0c839acc85ec0ef
Signed-off-by: Robert Jordens <jordens@gmail.com>
Reviewed-on: http://openocd.zylin.com/4187
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

tcl/interface/ftdi/digilent_jtag_smt2_nc.cfg

@@ -0,0 +1,18 @@
+#
+# Digilent JTAG-SMT2-NC
+#
+# http://store.digilentinc.com/jtag-smt2-nc-surface-mount-programming-module/
+# https://reference.digilentinc.com/_media/jtag_smt2nc/jtag-smt2-nc_rm.pdf
+#
+# Based on reference sheet (above) and Xilinx KCU105 schematics
+# https://www.xilinx.com/products/boards-and-kits/kcu105.html#documentation
+#
+# Note that the digilent_jtag_smt2 layout does not work and hangs while
+# the ftdi_device_desc from digilent_hs2 is wrong.
+
+interface ftdi
+ftdi_device_desc "Digilent USB Device"
+ftdi_vid_pid 0x0403 0x6014
+ftdi_channel 0
+ftdi_layout_init 0x00e8 0x60eb
+reset_config none