libcamera: v4l2_controls: Move V4L2ControlId out of V4L2ControlInfo

In order to reconcile the libcamera and V4L2 control info maps, we need
to move the V4L2ControlId embedded in V4L2ControlInfo map out of the
class. Store the V4L2ControlId instances in the V4L2Device that creates
them, and only reference them from V4L2ControlInfo.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/v4l2_device.cpp

@@ -386,9 +386,10 @@ void V4L2Device::listControls()
 			continue;
 		}
 
+		controlIds_.emplace_back(utils::make_unique<V4L2ControlId>(ctrl));
 		ctrls.emplace(std::piecewise_construct,
 			      std::forward_as_tuple(ctrl.id),
-			      std::forward_as_tuple(ctrl));
+			      std::forward_as_tuple(*controlIds_.back().get(), ctrl));
 	}
 
 	controls_ = std::move(ctrls);