Leave the LSI ON.

On testing the SSBL in 2024 on the same board that development was done
on there were issues with it returning HAL_TIMEOUT from
HAL_RCC_OscConfig.

When this happened there were no LED error codes as this code runs
before the LED is initialized.

src/main/main.c

@@ -294,7 +294,7 @@ void SystemClock_Config(void)
     */
     RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI|RCC_OSCILLATORTYPE_HSE;
     RCC_OscInitStruct.HSEState = RCC_HSE_ON; // RCC_HSE_BYPASS ?
-    RCC_OscInitStruct.LSIState = RCC_LSI_OFF;
+    RCC_OscInitStruct.LSIState = RCC_LSI_ON;
     RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
     RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     RCC_OscInitStruct.PLL.PLLM = 4;