mac802154: fix hold rtnl while ioctl

This patch fixes an issue to set address configuration with ioctl.
Accessing the mib requires rtnl lock and the ndo_do_ioctl doesn't hold
the rtnl lock while this callback is called. This patch do that
manually.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reported-by: Matteo Petracca <matteo.petracca@sssup.it>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/mac802154/iface.c

@@ -62,8 +62,7 @@ mac802154_wpan_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 		(struct sockaddr_ieee802154 *)&ifr->ifr_addr;
 	int err = -ENOIOCTLCMD;
 
-	ASSERT_RTNL();
-
+	rtnl_lock();
 	spin_lock_bh(&sdata->mib_lock);
 
 	switch (cmd) {
@@ -90,6 +89,7 @@ mac802154_wpan_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	case SIOCSIFADDR:
 		if (netif_running(dev)) {
 			spin_unlock_bh(&sdata->mib_lock);
+			rtnl_unlock();
 			return -EBUSY;
 		}
 
@@ -112,6 +112,7 @@ mac802154_wpan_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	}
 
 	spin_unlock_bh(&sdata->mib_lock);
+	rtnl_unlock();
 	return err;
 }