Although there was plenty of star wattage at the 25th Palm Springs International Film Festival Saturday night there was even more electricity than usual because some genuine rock royalty was in attendance. U2’s Bono and The Edge were on hand to accept the Sonny Bono Visionary Award, which acknowledged their major humanitarian work as well as their iconic musical contributions to the world. The award was well-timed as, like the rest of the honorees, they also have a song that is making waves this awards season. And it’s a very personal one. The band, and particularly Bono, had a long friendship with Nelson Mandela — who died December 5 — and their work in the anti-apartheid movement goes back to their beginnings as a band in the 1970s. And now they have written a song, “Ordinary Love” for the film of his life story, Mandela: Long Walk To Freedom. The Weinstein Company is hoping it will get the Oscar recognition that has eluded U2 before. They currently have a Golden Globe nomination for it, their sixth, with one win for 2002’s “The Hands That Built America” from Gangs Of New York.