Suppose that there is a winning strategy for the prisoners with $m<n-s$.
For an arbitrary sequence of steak allocations such that every prisoner eats steak, some $m$ prisoners will eventually vote for option 1. If we swap the meals of the $n-m$ other prisoners around, the $m$ prisoners cannot tell the difference, so they must vote for option 1 anyway. But $n-m>s$, so we can swap the meals of those $n-m$ such that one never eats steak.
This shows that a winning strategy is impossible for $m<n-s$.
If $m\ge n-s$$m=n-s$, we can use the same strategy that @matega described for the original problem. The $s$ prisoners who receive steak on the first day always vote for option 2, and the other $m$ vote for option 1 if they have received steak at least once.