There is no place to grease. Normally it is not needed, are you experiencing any issues?
Only folks who usually have trouble in that area are folks like me, but it's with corrosion and not grease. Probably safe to say your upper steering pin sits above the water line normally. The bearing is packed with grease when first installed and it gets very little movement and nothing to wash out the grease. On the other hand Formula built a 10K boat with one engine and there is only about 1/2 inch of my drive which is out of the water normally. So every so many years I have to replace the pin, seal and bearing. You should have no issue with this normally.