tlan: Restart autonegotiation on link loss

When link is lost on a card which uses internal PHY for 10 Mbit speeds,
restart autonegotiation to allow switching between 10 and 100 Mbps speeds.

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