Omar Johnson, the chief marketing officer who helped make Beats into a household name, is leaving the company next month, Fast Company reports. Johnson joined Beats as vice president of marketing in 2010 and was named CMO in 2012. His unique ad campaigns — which feature personal looks at the athletes and musicians who endorsed the product — catapulted the company to prominence in pop culture. In a statement, Beats co-founder Jimmy Iovine said,…