bnx2: Fix the behavior of ethtool when ONBOOT=no

I found a little bug.

When configure in ifcfg-eth* is ONBOOT=no,
the behavior of ethtool command is wrong.

    # grep ONBOOT /etc/sysconfig/network-scripts/ifcfg-eth2
    ONBOOT=no
    # ethtool eth2 | tail -n1
            Link detected: yes

I think "Link detected" should be "no".

Signed-off-by: Ooiwa Naohiro <nooiwa@miraclelinux.com>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>