netpoll: copy dev name of slaves to struct netpoll

Otherwise we will not see the name of the slave dev in error
message:

[  388.469446] (null):  doesn't support polling, aborting.
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1297,6 +1297,7 @@ static inline int slave_enable_netpoll(struct slave *slave)
 		goto out;
 
 	np->dev = slave->dev;
+	strlcpy(np->dev_name, slave->dev->name, IFNAMSIZ);
 	err = __netpoll_setup(np);
 	if (err) {
 		kfree(np);

net/bridge/br_device.c

@@ -243,6 +243,7 @@ int br_netpoll_enable(struct net_bridge_port *p)
 		goto out;
 
 	np->dev = p->dev;
+	strlcpy(np->dev_name, p->dev->name, IFNAMSIZ);
 
 	err = __netpoll_setup(np);
 	if (err) {