By Steve Ginsburg BALTIMORE (Reuters) – Baltimore Orioles first baseman Chris Davis is playing down his early season success despite putting up some eyebrow-raising numbers. The 27-year-old, six-year major league veteran clubbed an opposite-field grand slam in the eighth inning to lead the Orioles to a come-from-behind 9-5 victory over the Minnesota Twins on Friday. Davis joins Willie Mays (1971), Mark McGwire (1998) and Nelson Cruz (2011) as the only players to have hit home runs in the first four games of the season. …