Two years ago, Samsung set out its strategy to retain leadership in smartphones by investing more heavily in software and its own chips. Its plans have been only partially successful, as highlighted by a reshuffle at the top of the mobile business unit, with the elevation of a software-driven executive, Koh Dong Jin. Shin Jong Kyun, or JK Shin, steps back as head of the division, though he retains his co-CEO role for Samsung Electronics. The changes reflect growing desperation about Samsung’s smartphone business, which faces its lowest operating profit in four years in 2015, according to analysts. While the semiconductor business has been a source of growth and profit in recent quarters, and enabled Samsung to differentiate its Galaxy…