message: GAPI: fix warnings in own::Mat default generated constructors/assign op
diff: @@ -124,11 +124,11 @@ namespace cv { namespace gapi { namespace own {
  data = ptr(roi.y, roi.x);
  }
  - Mat(Mat const& src) = default;
  - Mat(Mat&& src) = default;
  + Mat(Mat const& ) = default;
  + Mat(Mat&& ) = default;
  - Mat& operator=(Mat const& src) = default;
  - Mat& operator=(Mat&& src) = default;
  + Mat& operator=(Mat const& ) = default;
  + Mat& operator=(Mat&& ) = default;
  /** @brief Sets all or some of the array elements to the specified value.
  @param s Assigned scalar converted to the actual array type.
  