bnx2x: Swap BCM8073 PHY polarity if required

Enable controlling BCM8073 PN polarity swap through nvm configuration, which is required in certain systems

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