igc: Remove unneeded hw_dbg prints

Remove unneeded hw_dbg prints from igc_ethtool.c file.
Clean up code.

Signed-off-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>