1) Goblins breed crazier than elves. They are immortal, like the latter, but also do not need to eat or drink - and while I'm not sure about the drinking part, [NO_EAT] certainly affects worldgen population growth. Removing [NO_EAT] and [NO_DRINK] from their raws and adding [MAXAGE:x:y] (I use the human 60:120 personally) should help with this.
2) Goblin entity raws, together with their [EVIL] creature tag, has them being able to settle anywhere but the good biomes. Other races can't do that, and the dwarves suffer the most here, as they are limited to mountains and nearby areas. You can add more settlement limitations to make goblin civ less expansive.
3) [LIKES_SITE:DARK_FORTRESS] and [TOLERATES_SITE:DARK_FORTRESS] tags increase the amount of goblins who move into the sites with uncapped population to breed there freely. Removing this tags from their entity raws will hinder their population growth a bit.
I have to warn you, though, that applying all three of these solutions at once may lead to goblins going extict instead, because, as PatrikLundell mentioned, their war politic is "all or nothing". So, try these one by one and see which one works best for you.
The last thing to take into account: dwarves are natural losers in the worldgen. First reason is that they never wage offensive wars and, thus, never conquer/reconquer new/lost sites. Second reason is Forgotten Beasts, which only attack dwarven fortresses and mountain halls and can easily destroy thousands of locals in a single raid. There isn't much that can be done about it, other than changing the dwarven site type. Better just deal with it.