Add STLINK/V2 interface config file.

Change-Id: I6df27ce619a5938ef854ff89bf76c6de4e122204
Signed-off-by: Mathias K <kesmtp@freenet.de>
Reviewed-on: http://openocd.zylin.com/286


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

tcl/interface/stlink-usb.cfg

+#
+# STMicroelectronics ST-LINK/V2 in-circuit debugger/programmer
+#
+
+interface stlink
+stlink_layout usb
+stlink_device_desc "ST-LINK/V2"
+stlink_vid_pid 0x0483 0x3748
+#
+# dummy values, not really needed
+#
+adapter_khz 1
+reset_config trst_and_srst
\ No newline at end of file