net: wwan: iosm: fix memory leak in ipc_wwan_dellink

IOSM driver registers network device without setting the
needs_free_netdev flag, and does NOT call free_netdev() when
unregisters network device, which causes a memory leak.

This patch sets needs_free_netdev to true when registers
network device, which makes netdev subsystem call free_netdev()
automatically after unregister_netdevice().

Fixes: 2a54f2c7 ("net: iosm: net driver")
Signed-off-by: HW He <hw.he@mediatek.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Zhaoping Shu <zhaoping.shu@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wwan/iosm/iosm_ipc_wwan.c

@@ -168,6 +168,7 @@ static void ipc_wwan_setup(struct net_device *iosm_dev)
 	iosm_dev->max_mtu = ETH_MAX_MTU;
 
 	iosm_dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+	iosm_dev->needs_free_netdev = true;
 
 	iosm_dev->netdev_ops = &ipc_inm_ops;
 }