doc: Fix minor typos
doc: Fix minor typos

 - config.xml -> package.xml
 - Update.xml -> Updates.xml

Change-Id: I94cd1b316a8591f24cea50153f071976800ed771
Reviewed-by: Niels Weber <df24410c43e1f71d7f720aa26e4fcb77ce70f242@digia.com>

olear/qtifw,olear/qtifw,olear/qtifw,olear/qtifw