[VIA_VELOCITY]: Don't oops on MTU change.

Simple mtu change when device is down.
Fix http://bugzilla.kernel.org/show_bug.cgi?id=9382.
Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/via-velocity.c

@@ -1963,6 +1963,11 @@ static int velocity_change_mtu(struct net_device *dev, int new_mtu)
 		return -EINVAL;
 	}
 
+	if (!netif_running(dev)) {
+		dev->mtu = new_mtu;
+		return 0;
+	}
+
 	if (new_mtu != oldmtu) {
 		spin_lock_irqsave(&vptr->lock, flags);