bonding: fix device leak on error in bond_create()

When the register_netdevice() call fails, the newly allocated device is
not freed.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -4946,6 +4946,8 @@ int bond_create(struct net *net, const char *name)
 	}
 
 	res = register_netdevice(bond_dev);
+	if (res < 0)
+		goto out_netdev;
 
 out:
 	rtnl_unlock();