Yeah, I'm pretty sure the neck restraint is considered a form of the chokehold.I'm not sure the placement of the knee makes a difference. Based on testimony I have seen, it appears the knee to the neck would obstruct blood flow. The weight of the knee, along with two other officers weight, would obstruct the ability to inhale.
In the manual, MN Statute 609.06, it defines chokehold as "a method by which a person applies sufficient pressure to make breathing difficult or impossible, including, but not limited to, throat or windpipe that may prevent or hinder breathing or reduce intake of air..."