bnx2x: Fix link issue for BCM8727 boards.

This patch fixes a link problem on BCM57712 + BCM8727 designs in which the TX
laser is controller by GPIO, after 1.60.xx drivers were previously loaded.
On these designs the TX_LASER is enabled by logic AND between the PHY
(through MDIO), and the GPIO. When an old driver is used, it disables the
MDIO part, hence the GPIO control had no affect de facto.

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>