libcamera: controls: Store reference to the InfoMap

Store a reference to the ControlInfoMap used to create a ControlList and
provide an operation to retrieve it. This will be used to implement
serialization of ControlList.

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>

include/libcamera/controls.h

@@ -233,12 +233,16 @@ public:
 	const ControlValue &get(unsigned int id) const;
 	void set(unsigned int id, const ControlValue &value);
 
+	const ControlInfoMap *infoMap() const { return infoMap_; }
+
 private:
 	const ControlValue *find(unsigned int id) const;
 	ControlValue *find(unsigned int id);
 
 	ControlValidator *validator_;
 	const ControlIdMap *idmap_;
+	const ControlInfoMap *infoMap_;
+
 	ControlListMap controls_;
 };