IT'S riots, riots all the way for Herman's Hermits and Wayne Fontana and the Mindbenders on their tour of the States. American fans are teeming around them everywhere they go, and the police and security men are literally at full stretch to keep off eager-beaver enthusiasts and autograph hunters.     The package, which also includes Sam the Sham and the Shangri-Las has been moving through the sun-drenched southern states of the U.S. Places like MIAMI with skyscrapers of luxury, and a swimming pool never far away to cool off from the constant heat.     Herman, Wayne and the others stayed at a ritzy hotel on the beach of Miami. They enjoyed a bathe in the blue Atlantic before filing in to a Press Conference on the sands, looking fresh and frisky in spite of late nights and early morning departures for the next venue.