The ControlList::contains(const ControlId &id) function isn't used, as
it has been replaced by usage of the get() function. Document get as
being the preferred way to check for the presence of a control in a
ControlList, and drop the contains() function.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>