igc: Remove _I_PHY_ID checking

i225 devices have only one PHY vendor. There is no point checking
_I_PHY_ID during the link establishment and auto-negotiation process.
This patch comes to clean up these pointless checkings.

Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>