By Chris Mannix His legacy on the line, Golovkin takes what could be his last stand this Saturday. View the original article to see embedded media. LAS VEGAS–Gennadiy Golovkin was smiling. And why shouldn’t he? More than three years after he last shared the ring with Canelo Alvarez, Golovkin, months removed from turning 40, was finally getting another shot. Moments after the obligatory stare-down that punctuated Tuesday’s grand arrivals, Golovkin broke out into a toothy grin. “I stopped hoping [the fight would happen] at some point,” Golovkin said. “I’m happy it is.” It has been 10 years since…