tcl/board: add Atmel SAM V71 Xplained Ultra

Tested with cmsis-dap using the EDBG chip on the board.

Change-Id: I3d398685c81e4701a9f6c1a66e60f7a87f839daa
Signed-off-by: Morgan Quigley <morgan@osrfoundation.org>
Reviewed-on: http://openocd.zylin.com/3092


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

tcl/board/atmel_samv71_xplained_ultra.cfg

+#
+# Atmel SAMV71 Xplained Ultra evaluation kit.
+# http://www.atmel.com/tools/ATSAMV71-XULT.aspx
+#
+# To connect using the EDBG chip on the dev kit over USB, you will
+# first need to source [find interface/cmsis-dap.cfg]
+# however, since this board also has a SWD+ETM connector, we don't
+# automatically source that file here.
+
+set CHIPNAME samv71
+
+source [find target/atsamv.cfg]