Now that all Extensible classes expose a _d() function that performs appropriate casts, the LIBCAMERA_D_PTR brings no real additional value. Replace it with direct calls to the _d() function. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>