tg3: allow ethtool -p to work for NICs in down state

Make tg3 behave like other drivers and let "ethtool -p" identify the
NIC even when it's in the DOWN state. Before this patch it would get an
error as follows if the NIC was down:

# ip link set down dev em4
# ethtool -p em4
Cannot identify NIC: Resource temporarily unavailable

With this patch ethtool identify works regardless of whether the NIC is up
or down as it does for other drivers.
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -12763,9 +12763,6 @@ static int tg3_set_phys_id(struct net_device *dev,
 {
 	struct tg3 *tp = netdev_priv(dev);
 
-	if (!netif_running(tp->dev))
-		return -EAGAIN;
-
 	switch (state) {
 	case ETHTOOL_ID_ACTIVE:
 		return 1;	/* cycle on/off once per second */