MEXICO CITY (Reuters) -Mexico, which has been subsidizing gasoline to soften price spikes, said on Saturday the policy would not apply in the U.S. border region this week, citing shortages as more Americans drive south to fill their tanks. The suspension of the subsidy from April 2-8 covers cities in the border states of Tamaulipas, Nuevo Leon, Coahuila, Chihuahua, Sonora and Baja California, including Tijuana, one of the world’s busiest border crossings. Mexico’s finance ministry said in a statement there was a gasoline shortage in the area “from an imbalance between supply and demand.” “In t…