The Mack is back! Fifteen years after he topped the charts with “Return of the Mack,” Mark Morrison stages a comeback with the celebratory video for “B’Day,” which he describes as the birthday anthem for the 21st century. The ’90s star hits a Miami club to party with his friend from across the pond, Trina, in the Gil Green-directed clip. Look for a new album from the Brit later this year.