igc: remove IGC_REMOVED function

igc driver has leftovers from the previous device that supported
Virtualization. This can be found in the function IGC_REMOVED which
became obsolete, and can be removed.

Signed-off-by: Vitaly Lifshits <vitaly.lifshits@intel.com>
Acked-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>