greybus: Documentation/sysfs: sort entries alphabetically

The attribute entries have been kept mostly sorted within each device
type. Let's move the three more-recently added interface attributes
that were not.

Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>