tg3: netdev_err() => dev_err()

Some uses of netdev_err() happen before the device has been registered.
This will cause the messages to be prepended with "(unregistered
net_device)" strings.  We can clean up the message by using dev_err()
instead.

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