net: Remove unused function first_net_device_rcu()

This is unused since commit f04565d ("dev: use name hash for
dev_seq_ops")

Signed-off-by: Yue Haibing <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Yue Haibing

include/linux/netdevice.h

@@ -3316,13 +3316,6 @@ static inline struct net_device *first_net_device(struct net *net)
 		net_device_entry(net->dev_base_head.next);
 }
 
-static inline struct net_device *first_net_device_rcu(struct net *net)
-{
-	struct list_head *lh = rcu_dereference(list_next_rcu(&net->dev_base_head));
-
-	return lh == &net->dev_base_head ? NULL : net_device_entry(lh);
-}
-
 int netdev_boot_setup_check(struct net_device *dev);
 struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type,
 				   const char *hwaddr);