This problem is not solved anywhere.
Big poker sites just don't let you withdraw your money if they suspect you of cheating in any way(assuming you win of course).
This is extremely difficult to be implemented(read impossible) in the blockchain in decentralized manner.
You may have blackjack, roulette , bingo, or any game that can be solved with single random seed AFTER all bets are placed.
Decentralized poker without trust... I'll be very happy if I see something like that.