bnx2x: Enable FC when parallel-detect is used

When parallel detect is used, flow-control is set to the
req_fc_auto_adv instead of none.

Motive: when 577xx is FC configuration is set to AUTO, while LP speed
is set to FORCE mode and FC to force RX/TX, link would come up using
parallel detect, and the FC will be set to NONE since FC capabilities
were not negotiated, although the LP is setting FC to force RX/TX.

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>