net: lan743x: Add support for EEPROM

Add new the EEPROM read and write access functions and system lock
protection to access by devices for PCI11010/PCI11414 chips

Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>