Even after Sunday’s hard-fought victory against the Minnesota Vikings, Chiefs running back Larry Johnson is still frustrated with the offense.  Johnson — who is in 29th-place in the NFL in rushing, so far this season — says many coaches are too stubborn, or set in their ways, to change.  L.J. says football isn’t like a chess game, it’s more like checkers.  But he says those coaches, in their attempts to orchestrate every move right down to the nearest inch, sometimes make it seem more like trigonometry.  The Chiefs are practicing this week, for Sunday’s contest against the Chargers in San Diego.