bnx2x: Fix 578xx link LED

Fix 1G link LED for the BCM578xx-SFI/KR.

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>