By Abhirup Roy and Joseph White LAS VEGAS (Reuters) – As artificial intelligence becomes the new horsepower for car buyers, established automakers are redoubling efforts to match the digital features that set Tesla, BYD and other new rivals apart, industry executives and analysts said at the CES technology show in Las Vegas. More than a decade after Tesla debuted cars with software that could be upgraded over the air like a smartphone, established automakers are still running behind in efforts to develop what the industry calls “software-defined vehicles,” industry executives said this week. N…