Photo: Mary Kouw/CBS/Getty Images Even among legendary sports announcers, few become synonymous with the sport they cover. But after more than 40 years in the business, Jim Nantz is the undisputed voice of golf, and particularly the Masters — its premier event. For tens of millions of Americans, he’s also woven into the audio fabric of NFL and college basketball broadcasts. Nantz’s buttery-smooth tone and easy delivery bring to mind Steve Jobs’s line about how it takes a lot of work to make