tulip: Poll link status more frequently for Comet chips

It now takes up to 60 seconds to detect cable (un)plug on ADMtek Comet chips.
That's too slow and might cause people to think that it doesn't work at all.

Poll link status every 2 seconds instead of 60 for ADMtek Comet chips.
That should be fast enough while not stressing the system too much.

Tested with ADMtek AN983B.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: David S. Miller <davem@davemloft.net>