bnx2x: Remove setting XAUI low-power for BCM8073

A rare link issue with the BCM8073 PHY may occur due to setting XAUI low power mode, while the PHY microcode already does that.
The fix is not to set set XAUI low power mode for this PHY.

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>