DETROIT — General Motors is laying off more than 1,000 salaried employees globally in its software and services division following a review to streamline the unit’s operations, CNBC has learned. The layoffs, including roughly 600 jobs at GM’s tech campus near Detroit, come less than six months after leadership changes overseeing the operations, including former Apple executive Mike Abbott leaving the automaker after less than a year in March due to health reasons. “As we build GM’s future, we must simplify for speed and excellence, make bold choices, and prioritize the investments that will have the greatest impact,” a GM...