If you bend the steering tie rod, then you can't adjust it as easily. If that is not a concern, then maybe just weld a bung on the end at an angle instead of straight into the tube. That way the tube stays straight which is stronger, but the end is angled properly.
I'm assuming the ATV upright is like the one in the picture where the steering arm is not remove able? Maybe making a piece that bolts through the existing hole but then adapts to the proper angle for the rod end would be good, but it's hard to do that without changing the effective length of the steering arm, or it's lateral position which would affect Ackerman geometry.
I guess I don't really have a good solution for you, sorry.
This is one of the reasons I stopped using ATV uprights and started making my own.