Quality steerers are very beefy for about 2" upward from the crown. They're way overbuilt there because it's the one failure most to be avoided.

That means there's a deep reserve and the fork may still be safe. In fact, it may st8ill be much stronger than many forks built with less overbuilt steerers (fairly common).

I can't say if it's safe, only that it may no be unsafe. If you're on the fence, but really want to use this fork, you might get some dowel rod, shave it to a tight fit and jam 2" up from the bottom. The brake bolt will keep it in place, and it will act as a safety net should the steerer fail.

Wooden "safety nets" were SOP in forks for decades, so it's not like this is some kind of crazy thing. However, in the end it's your bike and decision.