Porsche’s $10.9bn fourth-quarter profit, driven by a $2.4bn revenue gain from the North American A-class, helped the company beat analysts’ estimates for the year.The company earned $8.8bn in profit for the quarter, or a $1.9 billion profit margin.Porsche’s profits rose from $8bn a year ago to $9.9b in the quarter.Porsche, whose iconic 911 is the…