Paulo Costa says his fight with Robert Whittaker is not official for UFC 284. The promotion announced Costa (14-2 MMA, 6-2 UFC) will be facing Whittaker (24-6 MMA, 15-4 UFC) on Feb. 11 in Perth, Australia, but the Brazilian says he’s yet to receive or sign a contract for the fight. “This fight is one of my favorite fights that I wanted to make because I appreciate the fighter that Robert is,” Costa told Submission Radio. “He’s very good. Since I saw him fight, I thought, I want to fight this guy because he’s savage, you know – he puts…