ixgbe: add support for quad-port x520 adapter

This is a x520 based quad-port (4x10Gbps) NIC with a single QSFP+
connector.  Changes were required to our identify functions due to
different eeprom address which is also included here.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>