bnx2x: Fix BCM84833 link

BCM84833 fail to link due to incorrect auto-negotiation setting.

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>