Merge branch 'Eman869-fix_lpuart_hsi_power_consumption' of ssh://github.com/Eman869/mbed-os into Eman869-Eman869-fix_lpuart_hsi_power_consumption

Author: Cruz Monrreal II

targets/TARGET_STM/serial_api.c

@@ -536,7 +536,9 @@ HAL_StatusTypeDef init_uart(serial_t *obj)
 #if defined(LPUART1_BASE)
     if (huart->Instance == LPUART1) {
         if (obj_s->baudrate <= 9600) {
+#if ((MBED_CONF_TARGET_LPUART_CLOCK_SOURCE) & USE_LPUART_CLK_LSE)            
             HAL_UARTEx_EnableClockStopMode(huart);
+#endif            
             HAL_UARTEx_EnableStopMode(huart);
         } else {
             HAL_UARTEx_DisableClockStopMode(huart);