Update LittleFS to latest upstream head (esp8266#6986)

earlephilhower · web-flow · commit 753b5a581ab6 · 2020-01-04T09:59:06.000-08:00
diff --git a/libraries/LittleFS/lib/littlefs b/libraries/LittleFS/lib/littlefs
@@ -1 +1 @@
-Subproject commit 6b65737715039ef92d348014316b575b52547019
+Subproject commit ce2c01f098f4d2b9479de5a796c3bb531f1fe14c
