Medtronic is keeping its dividend streak going, but the recent increase isn't likely to be a meaningful one for many dividend investors.Dividend growth stocks can make for excellent long-term investments. Their ongoing rate increases allow investors to generate more in dividend income than if they were to just invest in a stale dividend with no increases, and which inflation chips away at over time.Medical device maker Medtronic (MDT -1.15%) falls into the category of a dividend growth stock. The company, w ...