cfg: add stm32ldiscovery board config

Change-Id: I392fdc4c588783fda1c7d4d6413b86ae9aa3f6b9
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/442
Tested-by: jenkins
Reviewed-by: Peter Stuge <peter@stuge.se>

tcl/board/stm32ldiscovery.cfg

@@ -0,0 +1,6 @@
+# This is an STM32L discovery board with a single STM32L152RBT6 chip.
+# http://www.st.com/internet/evalboard/product/250990.jsp
+
+source [find interface/stlink-v2.cfg]
+
+source [find target/stm32lx_stlink.cfg]