MADRID — Spain’s Supreme Court has overturned the convictions of four people charged with distributing pro-Nazi books and other materials through a shop and association in the northeastern city of Barcelona.The court said Friday that the men could be found guilty only if they had incited people to commit Nazi-type crimes. It ruled the Constitution does not prohibit ideologies, no matter how repulsive they may be.The four were linked to the now-closed Kalki bookshop and Circle for Indo-European Studies. They were convicted in 2009 by a Barcelona court and sentenced to prison terms of up to three and a half years.The books and publications they disseminated defended the Holocaust and incited genocide and racial hatred.