form 6198 is used to limit the deductibility of losses when you're not at risk - for an MLP that would mean you have zero (or negative tax basis). we have no way of telling if this is the case. take this as a generality, every K-1 from an MLP that I've worked with reflects tax basis in schedule L. so if ending capital is negative you're not at risk. Turbotax would have asked a question "all investment in partnership is at-risk" if you check it you're at risk there will be no 6198. if you don't answer it the next question is "some investment in partnership is not at-risk" only checking this would take you to form 6198. read the following
from an investor's guide to k-1 package support states the following for an MLP "ending capital account represents your basis in the partnership at the end of the tax year"
so if ending capital is positive form 6198 was not needed. and if it was positive at the beginning of the year it was not needed last year. you should check the first question all at-risk.
