libcamera: media_device: Make open() and close() private

All external callers to open() and close() have been refactored and
there is no need to expose these functions anymore, make them private.

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

src/libcamera/include/media_device.h

@@ -30,9 +30,6 @@ public:
 	void release();
 	bool busy() const { return acquired_; }
 
-	int open();
-	void close();
-
 	int populate();
 	bool valid() const { return valid_; }
 
@@ -62,6 +59,9 @@ private:
 	bool valid_;
 	bool acquired_;
 
+	int open();
+	void close();
+
 	std::map<unsigned int, MediaObject *> objects_;
 	MediaObject *object(unsigned int id);
 	bool addObject(MediaObject *object);