libcamera: request: Use external CameraControlValidator

Each Request is currently creating its own CameraControlValidator
using the Camera instance at construction.

Now that the Camera exposes its own CameraControlValidator on its
private interface, use that one on all Requests.

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

include/libcamera/request.h

@@ -71,7 +71,6 @@ private:
 	bool completeBuffer(FrameBuffer *buffer);
 
 	Camera *camera_;
-	CameraControlValidator *validator_;
 	ControlList *controls_;
 	ControlList *metadata_;
 	BufferMap bufferMap_;