ixgbe: Filter out spurious link up indication

Add delayed link state recheck to filter false link up indication
caused by transceiver with no fiber cable attached.

Signed-off-by: Sebastian Czapla <sebastianx.czapla@intel.com>
Tested-by: Sunitha Mekala <sunithax.d.mekala@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>