This patch refactors NVM read functions in order to accommodate i210 devices
that do not have a flash.  Previously, this was not supported on i210
devices.
Signed-off-by: NCarolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>