bnx2x: Modify BCM8706 link init seq

Modify BCM8706 link initialization sequence so that first it link up
between Serdes and BCM8706, and only then between BCM8706 to network

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>