There’s no smoke without fire, so they say, and this week, the rumors regarding AT&T ditching DirecTV have flared up again. This time around, two private equity firms have been linked to the assets, but AT&T is still denying it wants to offload the satellite TV network. We have long expected AT&T to kill off DirecTV, after converting as many of its higher-ARPU subs over to AT&T-branded offerings. Once bled dry, getting $20 billion for the carcass would be something of a coup, but then the question becomes what firm would want to buy this husk? One potential suitor is Platinum Equity which was founded in 1995, and remains a privately held American firm. Its portfolio is quite extensive, but…