igc: Remove unreachable code from igc_phy.c file

Address community comment.
Remove the unreachable code leads to the static checker warning.
PHY functionality will be added later per demand.
Reported by Dan Carpenter.

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>