bnx2x: Fix BCM57810-KR FC

Fix 57810-KR flow-control handling link is achieved via CL37 AN.

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>