removed unnecessary note

Resources/doc/reference/installation.rst

@@ -84,11 +84,6 @@ forget to enable SonataAdminBundle too:
         );
     }
 
-.. note::
-
-    If a dependency is already enabled somewhere in your ``AppKernel.php``,
-    you don't need to enable it again.
-
 .. note::
 
     Since version 2.3 SonatajQueryBundle is not required anymore as assets are available in this