The death watch for O.J. Simpson was highly controlled to prevent leaks emerging before Simpson’s death Wednesday at the age of 76, according to a new report. As Simpson was losing his final battle with prostate cancer, visitors who came to see him at his home were required to sign non-disclosure agreements, according to TMZ. Phones were banned from the house, TMZ also reported, citing sources it did not name. The report said that as of Friday, April 5, when Simpson seemed unlikely to recover, friends and family began to make their final calls. TMZ estimated between 30 and 50 people came to se…