Fight! “Mortal Kombat II” is gearing up for a box office battle this weekend with last week’s champ, “The Devil Wears Prada 2.” The Warner Bros. and New Line action movie has made $5.2 million in Thursday previews. Based on the popular, violent video game franchise, “Mortal Kombat II” is expected to make $40 million to $45 million this weekend, though Warner Bros. is playing it safer with a $35 million prediction. It’ll be a close showdown with 20th Century Studios’ “The Devil Wears Prada 2,”