Add openOCD config

stm32f4discovery.cfg

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# This is an STM32F4 discovery board with a single STM32F407VGT6 chip.
+# http://www.st.com/internet/evalboard/product/252419.jsp
+
+source [find interface/stlink.cfg]
+
+transport select hla_swd
+
+# increase working area to 64KB
+set WORKAREASIZE 0x10000
+
+source [find target/stm32f4x.cfg]
+
+reset_config srst_only