bnx2x: Utilize Link Flap Avoidance

Change various flows in the bnx2x driver which up until now flapped
the link - these flows now benefit from the link flap avoidance mechanism.

This includes the removal of the link reset made upon nic init, as it is
possible the link is already active at that time.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Yaniv Rosner <yaniv.rosner@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>