Jonny Depp was like the second coming of the Beatles last night in Westwood for the premiere of Michael Mann’s “Public Enemies,” which screened as the Centerpiece gala at the Los Angeles Film Festival. After the arrival of his limos, Jonny and his entourage headed across the street to screaming crazed fans to sign autographs, then headed to another corner with screaming fans behind barricades (security had to hold back the …