libcamera: control_serializer: Save serialized ControlInfoMap in a cache

The ControlSerializer saves all ControlInfoMaps that it has already
(de)serialized, in order to (de)serialize ControlLists that contain the
ControlInfoMaps. Leverage this to cache ControlInfoMaps, such that the
ControlSerializer will not re-(de)serialize a ControlInfoMap that it has
previously (de)serialized.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/internal/control_serializer.h

@@ -33,6 +33,8 @@ public:
 	template<typename T>
 	T deserialize(ByteStreamBuffer &buffer);
 
+	bool isCached(const ControlInfoMap &infoMap);
+
 private:
 	static size_t binarySize(const ControlValue &value);
 	static size_t binarySize(const ControlInfo &info);