MTS_DRAGONFLY_F413RH - fix lpticker

Author: Ben Cooke

targets/targets.json

@@ -4530,13 +4530,18 @@
                 "help": "This target supports LPTIM. Set value 1 to use LPTIM for LPTICKER, or 0 to use RTC wakeup timer",
                 "value": 1
             },
+            "clock_source": {
+                "help": "USE_PLL_HSE_XTAL | USE_PLL_HSI",
+                "value": "USE_PLL_HSE_XTAL|USE_PLL_HSI",
+                "macro_name": "CLOCK_SOURCE"
+            },
             "hse_value": {
                 "help": "HSE via 26MHz xtal",
                 "value": "26000000",
                 "macro_name": "HSE_VALUE"
             }
         },
-        "overrides": { "lpticker_delay_ticks": 4, "tickless-from-us-ticker": true},
+        "overrides": { "lpticker_delay_ticks": 4, "tickless-from-us-ticker": true, "lse_available": 0},
         "detect_code": ["0316"],
         "macros_add": [
             "MBED_TICKLESS",