It depends on a lot of variables, many of which Riot keeps private. It took me about 125 games per checkpoint (and about 180 for the honor unlock) without any validated reports since my chat restrict, as confirmed by Support on a weekly basis (I check in with them regularly). For some of my friends, it took about the same, while others it took much less. I'm on the final checkpoint now, almost at Honor 2 and it has been an arduous journey. All you can do is just play and spam games (as Riot Support instructs you to do) and make sure to minimize your usage of chat to compliments and team communication. Stick to shorter game modes, such as Co-op Vs AI (3v3 is best for this), ARAM, and Nexus Blitz. Don't expect it to be an easy climb back. You can open a ticket or live chat with Support if you're worried about your progress, and they can check if you've been validly reported (which slows honor) or not. Good luck.