pkg/spiffs: set SPIFFS_ALIGNED_OBJECT_INDEX_TABLES by default

This enforce right memory alignment of page object header struct.
If this flag is not set, hard fault can be generated (at least on Cortex-M0)

pkg/spiffs/include/spiffs_config.h

@@ -208,7 +208,7 @@ void spiffs_unlock(struct spiffs_t *fs);
 
 // Enable this if your target needs aligned data for index tables
 #ifndef SPIFFS_ALIGNED_OBJECT_INDEX_TABLES
-#define SPIFFS_ALIGNED_OBJECT_INDEX_TABLES       0
+#define SPIFFS_ALIGNED_OBJECT_INDEX_TABLES       1
 #endif
 
 // Enable this if you want the HAL callbacks to be called with the spiffs struct