After winning a Grammy this past month, the Reggae singer( pictured above)now faces a long-term stint in prison over drug charges. Reggae star Buju Banton was convicted on Tuesday in a Florida court on drug charges. He now faces up to 15 years in prison, stemming from three of four federal counts."Obviously, we are all upset and disappointed and emotional," said Banton's lawyer, David Markus, aft…