“Game of Thrones” Season 7 cast members now include Oscar winner Jim Broadbent. Although the 67-year-old veteran British performer has not yet disclosed his role, Entertainment weekly confirms that the acclaimed actor will play a ‘significant role’. GOT 7 Cast: Jim Broadbent as Westeros maester? Broadbent, who played Professor Horace Slughorn in the Harry Potter franchise and grabbed the Academy …