The dodongo was more of a nuisance for the Gorons since it blocked them off from their food source. I do not think they would have adopted one as their guardian deity. In FSA the Gorons were having trouble with the dodongos and needed Link's help in killing them. Since they use dodongo hides for the creation of things like the red tunic and use the bones of a massive one to mark the entrance of the cavern, I do not think they worship it in any way. They just use the leftover parts for items or decoration. There is nothing there to make it seem like the large skull was an object of worship in any way.
Although in Spirit Tracks they did have a goddess of the mountain that they kept an altar to and one Goron prayed to in the game. There is even a goron named Kagoron that acs as the messenger, very similar to Medlii and Valoo and Ruto and Jabu Jabu before.
"The last eruption blocked the way into the village. I fear the mountain goddess must be very angry.
"Kagoron is the mountain goddess's messenger. He is praying at her altar for a stop to the volcano's outbursts. But because of the eruptions, the path to the altar is very dangerous! Go with caution!" — A Goron
Considering the Goron's appreciation for strength and power, as well as being the guardians of the spiritual stone of fire, and worshipping a goddess of a mountain, they might be worshipping Din. Since Din was the goddess responsible for creating the mountains in the mythology of the game, as well as staining the earth red, and her spell in OoT was called Din's Fire. She has a strong connection to fire and earth.
"Din... With her strong flaming arms, she cultivated the land and created the red earth."
The Gorons have the same connection to fire, mountains, and strength. They live near the Fire temple in OoT, are unaffected by lava of the mountain, and in ST live in the Fire Realm of new Hyrule.