Well, I have a small theory on this actually.
We have seen the Mogmas in the E3 2011 SS trailer, there they were located in a landscape very similar to what Death Mountain looks like in TP, so I think it is Death Mountain. In the later Comic Con SS trailer we saw an actual Goron, however, he was located in the forest. Now I think that the Gorons originally were forest living creatures, and that the Mogmas were the ones who lived in the mountains. It is possible that some time during the game the Mogmas somehow leave Hyrule (they all die, or they abandon the kingdom). After those events the Gorons, who after all is a rock tribe, will settle down in Death Mountain and live there happily together until Ganon makes Death Mountain a dark and evil place in LoZ on the Child Timeline, or until the entire Kingdom of Hyrule is flooded in the events before WW on the Adult Timeline.