It ain't a trademark infringement unless Apple has gotten the logo registered as trademark specifically for the class of services/goods that the restaurant is selling, i.e., food.
Well, Apple threatened this Canadian school of business cause they claim their logo looks too much like the Apple logo...
http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20081004/BC_Apple_Threatens_Suit_081004/20081005