WASHINGTON (Reuters) - Roger Ailes, the Fox News chairman ousted last month after sexual harassment allegations, is not advising Republican presidential candidate Donald Trump before the presidential debates in the fall, the campaign said on Tuesday. “He is not advising Mr. Trump or helping with debate prep. They are longtime friends but he has no formal or informal role in the campaign,” the campaign said.  Earlier, the New York Times had reported that Ailes was advising Trump ahead of the Sept. 26 first presidential debate with Democratic rival Hillary Clinton in a role that could stretch beyond the initial Long Island, New York debate.  Ailes resigned from his post as chairman and chief executive of Fox News Channel last month, ending his 20-year reign over the conservative cable news channel, after Fox anchor Gretchen Carlson sued the 76-year-old claiming sexual harassment.  Trump has spoken highly of Ailes in the past, calling him “a great guy” in a tweet last month.  