Add a config_odev_get_attribute helper, and replace the diy looping over all
the attributes done in various places with calls to this helper.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>