A man who climbed to the top of the Tobin Bridge last night was talked down by state police negotiators after a tense, two-hour ordeal that tied up the evening commute.The man was reported climbing the bridge at 7 p.m., and the scene was cleared just after 9 p.m.Southbound traffic was diverted to East Boston during that time as emergency personnel responded to the upper deck of the bridge.At one point, the man could be seen at the crown of the Tobin as he talked on a cellphone.