bnx2x: Saving PHY FW version

Some PHYs (like the BCM8726) FW version cannot be read after activating the
PHY, so we need to save this information

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>