net: ethoc: enable NAPI before poll may be scheduled

commit d220b942 upstream.

ethoc_reset enables device interrupts, ethoc_interrupt may schedule a
NAPI poll before NAPI is enabled in the ethoc_open, which results in
device being unable to send or receive anything until it's closed and
reopened. In case the device is flooded with ingress packets it may be
unable to recover at all.
Move napi_enable above ethoc_reset in the ethoc_open to fix that.

Fixes: a1702857 ("net: Add support for the OpenCores 10/100 Mbps Ethernet MAC.")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/net/ethernet/ethoc.c

@@ -706,6 +706,8 @@ static int ethoc_open(struct net_device *dev)
 	if (ret)
 		return ret;
 
+	napi_enable(&priv->napi);
+
 	ethoc_init_ring(priv, dev->mem_start);
 	ethoc_reset(priv);
 
@@ -718,7 +720,6 @@ static int ethoc_open(struct net_device *dev)
 	}
 
 	phy_start(priv->phy);
-	napi_enable(&priv->napi);
 
 	if (netif_msg_ifup(priv)) {
 		dev_info(&dev->dev, "I/O: %08lx Memory: %08lx-%08lx\n",