Most storytelling concepts that have names that sound like the name of a person can be traced to an actual person, real or fictitious. (Foley, Mary Sue, etc.) But I've never come across an explanation for the origin of the term "McGuffin". Who was McGuffin, and why are artifacts that drive the plot named after him?
The name MacGuffin does not originate from a particular person's name. It's just a nonsense term that has been around before it was applied to the movie concept of a random item that drives the plot.
Tvtropes attributes Alfred Hitchcock with making the term MacGuffin famous, and Hitchcock himself names one of his screenwriters, Angus McPhail, as the creator of the word:
Wikipedia gives a very similar story with additional background information, and giving various books about Hitchcock as the source of the information.
It should be noted that the concept existed in movies before the term MacGuffin was coined for it:
We don't know for sure if the joke is the original source of the term, but it seems very likely. However there is no indication that there was any person named MacGuffin that was the source of this term.