By Borja Suarez and Graham Keeley EL HIERRO, Spain (Reuters) – Hopes of finding any of the 48 migrants missing since their boat sank near the Spanish island of El Hierro are diminishing, authorities said on Sunday, in what threatens to be the deadliest such incident in 30 years of crossings from Africa to the Canary Islands. Nine people, one of them a child, had earlier been confirmed as dead…