bnx2x: Add RJ45 SFP module detection

Add RJ45 SFP module detection. In case the user set 10G link speed, and the
module doesn't support it, then force the speed to 1G and notify the user.

Signed-off-by: Yaniv Rosner <yanivr@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>