batman-adv: invoke dev_get_by_index() outside of is_wifi_iface()

Upcoming changes need to perform other checks on the
incoming net_device struct.

To avoid performing dev_get_by_index() for each and every
check, it is better to move it outside of is_wifi_iface()
and search the netdev object once only.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

net/batman-adv/hard-interface.h

@@ -41,6 +41,7 @@ enum batadv_hard_if_cleanup {
 
 extern struct notifier_block batadv_hard_if_notifier;
 
+bool batadv_is_wifi_netdev(struct net_device *net_device);
 struct batadv_hard_iface*
 batadv_hardif_get_by_netdev(const struct net_device *net_dev);
 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
@@ -51,7 +52,6 @@ void batadv_hardif_remove_interfaces(void);
 int batadv_hardif_min_mtu(struct net_device *soft_iface);
 void batadv_update_min_mtu(struct net_device *soft_iface);
 void batadv_hardif_free_rcu(struct rcu_head *rcu);
-bool batadv_is_wifi_iface(int ifindex);
 
 static inline void
 batadv_hardif_free_ref(struct batadv_hard_iface *hard_iface)