How can I disable a USB port that is drawing too much power?
Short answer is no, you can't disable a USB port.  Additionally, if you are having this issue with nothing attached to it, it's definitely a hardware issue.

First thing is to do an SMC reset. 

If that doesn't fix the issue, you need to take it in for service because it's likely a logic board or component (connector issue).  If I had to guess, it would be a short to ground of the 5V power rail on the USB connector.  However, without actually getting hands on with it, it's only a hypothesis at best.