bnx2x: Limit 1G link enforcement

Change 1G-SFP module detection by verifying not only that it's not
compliant with 10G-Ethernet, but also that it's 1G-ethernet compliant.

Signed-off-by: Yaniv Rosner <Yaniv.Rosner@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>