tg3: Fix link down notify failure when EEE disabled

Occasionally, when the network cable is removed after a successful
autonegotiation, the device will not send a link down interrupt to the
driver.  This happens because of a bad interaction of an EEE
workaround.  The fix is to adjust the code so that the root cause
condition does not happen.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>