Fix OpenOCD board name for nucleo_l552ze_q

Resolve #576

Author: valeros

boards/nucleo_l552ze_q.json

@@ -19,7 +19,7 @@
     "onboard_tools": [
       "stlink"
     ],
-    "openocd_board": "st_nucleo_l5.cfg",
+    "openocd_board": "st_nucleo_l5",
     "openocd_target": "stm32l5x",
     "svd_path": "STM32L552.svd"
   },