By Jason Buch and Dave Graham SAN ANTONIO/MEXICO CITY (Reuters) -The suspected driver of a truck packed with dozens of migrants who died in sweltering heat during a smuggling attempt in Texas and an accused conspirator were charged in U.S. federal court on Wednesday with human trafficking offenses. If convicted each man faces a maximum sentence of life in prison, or possibly the death penalty, the U.S. Justice Department said in announcing charges stemming from the deadliest migrant-trafficking incident on record in the United States. The death toll from the tragedy rose to 53 on Wednesday as …