Domo arigato, Mr. Obama.Fear not, classic rock obsessives: the global economic crisis will not waylay this year's round of washed-up, amusement-park-haunting ghosts of '70s arena rock. In fact, a couple such bands are using all this talk of stimuli to their PR advantage. Behold, VH1 Classic and the video game Rock Band® present REO Speedwagon and Styx on the Can't Stop Rockin' Tour. In addition to recording a song together next month that will be called "Can't Stop Rockin'" (listen for it on a