Coding standard issues in FieldEntryFormController.php

While working on

#2466389: FieldEntryFormController::edit() should throw an exception / return 404 when no valid flagging entity is found.

I took the paranoid approach of running FieldEntryFormController.php through

phpcs --standard=Drupal

I found only side issues ... which I hope can be reviewed and committed in the blink of a eye :)