bnx2x: Enhance SFP+ module control

Add flexible support to control various SFP+ module features either throughout MDIO registers or GPIO pins according to NVRAM configuration

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>