There were many mornings that Mike Grier got up for school to learn that his dad had already left for work. There were many days that his dad wouldn’t make it home for dinner, or even for the kids’ bedtime. Bobby Grier was a coach and scout for the New England Patriots throughout the 1980s. Now Mike is the general manager of the Sharks, the first Black GM in the 105-year history of the National Hockey League. His brother Chris holds the same title with the NFL’s Miami Dolphins. “I think the main thing my father instilled in us was his work ethic,” the new Sharks GM said. “Just the time and eff…