Good intentions and fine performances could not rescue “Black or White” from drowning in a maudlin miasma of stereotypical predictability. “Elliott Anderson” (Kevin Costner) devastated by the loss of his wife, faces a custody battle over his biracial granddaughter, whom they raised since birth; their seventeen-year-old daughter died giving birth; “Eloise” (Jillian Estell) is an adorable seven-year-old, surrounded by affluence, …