By Victoria Waldersee and Supantha Mukherjee STOCKHOLM/BERLIN (Reuters) – Over a dozen automakers including Toyota and Nissan, have signed up with a platform for patent licences from 51 tech companies, aiming to simplify access to wireless technology and avoid costly legal battles. Conflicts have stemmed in part from different views among carmakers, suppliers and tech firms over who should shoulder the cost of licensing. Through independent licensing marketplace Avanci, carmakers gain access to patents for 2G, 3G and 4G technology from the likes of Finland’s Nokia, Sweden’s Ericcson and Taiwan…