You need to have the Goron Lullaby.
-Get the Lens of Truth from the back of the Goron Villiage
-Get the Goron Mask
-Get the Hot Spring Water in a bottle
-Thaw out the iced-over hole just before the gorn villiage
-Open the Goron City Complex
-Talk to the Goron Child as a Goron
-Go to the iced over hole
-Get more Hot Water
-Thaw out the Goron Elder
-Use the drums in front of him
-Play the Lullaby Fragment for the Goron Child