igb: Refactor of init_nvm_params

This patch refactors the init_nvm_params functions for 82575 and adds a new
function for the i210/i211 devices in order to configure separately the NVM
functionality for the i210/i211 family.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>