Add changelog entry for Exif orientation

Change-Id: I5c7218bad624ff5a834153091f06aa6ffed612b6
Reviewed-by: aavit <eirik.aavitsland@theqtcompany.com>

dist/changes-5.4.0

@@ -25,6 +25,10 @@ QtCore
  - Added QEnableSharedFromThis, a class that allows obtaining a
    QSharedPointer for an object already managed by a shared pointer.
 
+QtGui
+-----
+
+ - QImageReader now automatically rotates JPEG images according to Exif orientation
 
 QtSql
 -----