Merge pull request #13859 from jeromecoutant/PR_L4_LPUART_HSI

STM32L4: Use HSI for LPUART

Author: 0xc0170

targets/targets.json

@@ -3328,6 +3328,9 @@
         "extra_labels_add": [
             "STM32L475xG"
         ],
+        "overrides": {
+            "lpuart_clock_source": "USE_LPUART_CLK_HSI"
+        },
         "macros_add": [
             "STM32L475xx",
             "MBED_SPLIT_HEAP"
@@ -3371,6 +3374,9 @@
         "components_add": [
             "FLASHIAP"
         ],
+        "overrides": {
+            "lpuart_clock_source": "USE_LPUART_CLK_HSI"
+        },
         "macros_add": [
             "STM32L476xx",
             "MBED_SPLIT_HEAP"
@@ -3434,6 +3440,9 @@
         "components_add": [
             "FLASHIAP"
         ],
+        "overrides": {
+            "lpuart_clock_source": "USE_LPUART_CLK_HSI"
+        },
         "macros_add": [
             "STM32L486xx",
             "MBEDTLS_CONFIG_HW_SUPPORT",
@@ -3458,8 +3467,7 @@
             "MCU_STM32L486xG"
         ],
         "overrides": {
-            "clock_source": "USE_PLL_HSE_XTAL",
-            "lpuart_clock_source": "USE_LPUART_CLK_HSI"
+            "clock_source": "USE_PLL_HSE_XTAL"
         },
         "detect_code": [
             "0460"
@@ -3481,6 +3489,9 @@
         "components_add": [
             "FLASHIAP"
         ],
+        "overrides": {
+            "lpuart_clock_source": "USE_LPUART_CLK_HSI"
+        },
         "macros_add": [
             "STM32L496xx"
         ]