bnx2x: Supporting PHY FW upgrade

There are 3 operations that the driver needs to support to allow applications to
access the PHY FW (on top of the MDC/MDIO access). Since those are essentially
nvram access commands, adding them to the ethtool -E interface.

Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>