bnx2x: Fix missing pause on for 578xx

When link speed is 1G and below, pause weren't sent due to missing pause setting in the UMAC.

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>