ixgbe: add support for 64k EEPROM for 82599

82599 supports up to 32k EEPROM addressing via EERD register. If we
wish to address larger EEPROM this have to be done via serial interface.
This patch adds function ixgbe_read_eeprom_82599 which selects the best
method to read the EEPROM.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Evan Swanson <evan.swanson@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>