Fix file.open in STM32 eeprom emu

Marlin/src/HAL/HAL_STM32F1/persistent_store_sdcard.cpp

     if (!card.isDetected()) return false;
 
     SdFile file, root = card.getroot();
-    if (file.open(&root, EEPROM_FILENAME, O_CREAT | O_WRITE | O_TRUNC))
-      return false;
-
-    int16_t bytes_written = file.write(HAL_STM32F1_eeprom_content, HAL_STM32F1_EEPROM_SIZE);
-    file.close();
+    int16_t bytes_written = 0;
+    if (file.open(&root, EEPROM_FILENAME, O_CREAT | O_WRITE | O_TRUNC)) {
+      bytes_written = file.write(HAL_STM32F1_eeprom_content, HAL_STM32F1_EEPROM_SIZE);
+      file.close();
+    }
     return (bytes_written == HAL_STM32F1_EEPROM_SIZE);
   }