Fixed sparse matrix assignment.

src/TNL/Containers/Segments/CSR.hpp

src/TNL/Containers/Segments/CSRView.h

src/TNL/Containers/Segments/CSRView.hpp

src/TNL/Containers/Segments/Ellpack.hpp

src/TNL/Containers/Segments/EllpackView.h

src/TNL/Containers/Segments/EllpackView.hpp

src/TNL/Containers/Segments/SlicedEllpack.hpp

src/TNL/Containers/Segments/SlicedEllpackView.h

src/TNL/Containers/Segments/SlicedEllpackView.hpp

src/TNL/Matrices/Dense.hpp

src/TNL/Matrices/DenseMatrixView.hpp

src/TNL/Matrices/MatrixView.hpp

src/TNL/Matrices/Multidiagonal.h

src/TNL/Matrices/Multidiagonal.hpp

src/TNL/Matrices/MultidiagonalMatrixView.h

src/TNL/Matrices/MultidiagonalMatrixView.hpp

src/TNL/Matrices/SparseMatrix.h

src/TNL/Matrices/SparseMatrix.hpp

src/TNL/Matrices/SparseMatrixView.hpp

src/TNL/Matrices/Tridiagonal.h