dm9000: handle initial link status

On the DM9000A/DM9000B force the initial check of the link status.  The
DM9000A/B has a link status changed event and this interrupt bit isn't
always set out of reset when a cable is plugged in.  This results in the
driver not seeing the cable attached link status until the cable is
removed and plugged in again.

Signed-off-by: Andrew Ruder <andrew.ruder@elecsyscorp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>