bnx2x: Add autogrEEEn support

Add autogrEEEn support on BCM84833 and 54618se, which allows to reduce power consumption.

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>