ARM|Driver: Add DPI Driver for emulation

This driver provides support for Cadence JTAG BFM

The "jtag_dpi" driver implements a JTAG driver acting as a client for the
SystemVerilog Direct Programming Interface (DPI) for JTAG devices.
DPI allows OpenOCD to connect to the JTAG interface of a hardware model
written in SystemVerilog, for example, on an emulation model of
target hardware.

Tested on Ampere emulation with Altra and Altra Max models

Change-Id: Iaef8ba5cc1398ee2c888f39a606e8cb592484625
Signed-off-by: Kevin Burke <kevinb@os.amperecomputing.com>
Signed-off-by: Daniel Goehring <dgoehrin@os.amperecomputing.com>
Reviewed-on: http://openocd.zylin.com/5573
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

tcl/interface/jtag_dpi.cfg

@@ -0,0 +1,38 @@
+#
+# Provide support for the Cadence JTAG BFM
+#
+# Copyright (c) 2020, Ampere Computing LLC
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program;
+#
+#
+
+adapter driver jtag_dpi
+
+# Set the DPI JTAG server port
+if { [info exists DPI_PORT] } {
+   set _DPI_PORT $DPI_PORT
+} else {
+   set _DPI_PORT 5555
+}
+
+# Set the DPI JTAG server address
+if { [info exists DPI_ADDRESS] } {
+   set _DPI_ADDRESS $DPI_ADDRESS
+} else {
+   set _DPI_ADDRESS "127.0.0.1"
+}
+
+jtag_dpi_set_port $_DPI_PORT
+jtag_dpi_set_address $_DPI_ADDRESS