50 Cent has reignited his long-running public feud with his eldest son, Marquise Jackson, after posting a clip from Power showing his character killing his own son in what many fans interpreted as a pointed response to Marquise's latest comments about child support and their fractured relationship. The post, shared on Instagram on Wednesday, came shortly after Marquise publicly offered to pay his father $6,700 for 24 hours of his time, saying he…