libcamera: request: Make controls_ a class instance

The controls_ member variable is a pointer, for no specific reason.
Make it an instance and simplify the class constructor and destructor.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>

include/libcamera/request.h

@@ -49,7 +49,7 @@ public:
 
 	void reuse(ReuseFlag flags = Default);
 
-	ControlList &controls() { return *controls_; }
+	ControlList &controls() { return controls_; }
 	const ControlList &metadata() const;
 	const BufferMap &buffers() const { return bufferMap_; }
 	int addBuffer(const Stream *stream, FrameBuffer *buffer,
@@ -67,7 +67,7 @@ public:
 private:
 	LIBCAMERA_DISABLE_COPY(Request)
 
-	ControlList *controls_;
+	ControlList controls_;
 	BufferMap bufferMap_;
 
 	const uint64_t cookie_;