event: fix comments syntax error

Fix comments syntax error in event description:
    creasted -> created

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/develop/event.rst b/doc/develop/event.rst
index 4ff5934..e60cbf6 100644
--- a/doc/develop/event.rst
+++ b/doc/develop/event.rst
@@ -12,7 +12,7 @@
 often easier to use an event.
 
 An event consists of a type (e.g. EVT_DM_POST_INIT) and some optional data,
-in `union event_data`. An event spy can be creasted to watch for events of a
+in `union event_data`. An event spy can be created to watch for events of a
 particular type. When the event is created, it is sent to each spy in turn.