libcamera: yaml_parser: Remove memberNames() function

Now that YamlObject supports iteration, the memberNames() function isn't
useful anymore as it can be implemented using utils::map_keys() if
really needed. Drop it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Han-Lin Chen <hanlinchen@chromium.org>

include/libcamera/internal/yaml_parser.h

@@ -172,7 +172,6 @@ public:
 
 	bool contains(const std::string &key) const;
 	const YamlObject &operator[](const std::string &key) const;
-	std::vector<std::string> memberNames() const;
 
 private:
 	LIBCAMERA_DISABLE_COPY_AND_MOVE(YamlObject)