nl80211: Note linux_set_iface_flags() failure in debug log

There was one final remaining linux_set_iface_flags() call that did not
check the result. This specific one does not really matter much, but
anyway, be more consistent by checking the result and log any error in
debug log. (CID 74146)

Signed-off-by: Jouni Malinen <j@w1.fi>

src/drivers/driver_nl80211.c

@@ -2150,7 +2150,11 @@ static void wpa_driver_nl80211_deinit(struct i802_bss *bss)
 			nl80211_handle_destroy(drv->rtnl_sk);
 	}
 	if (bss->added_bridge) {
-		linux_set_iface_flags(drv->global->ioctl_sock, bss->brname, 0);
+		if (linux_set_iface_flags(drv->global->ioctl_sock, bss->brname,
+					  0) < 0)
+			wpa_printf(MSG_INFO,
+				   "nl80211: Could not set bridge %s down",
+				   bss->brname);
 		if (linux_br_del(drv->global->ioctl_sock, bss->brname) < 0)
 			wpa_printf(MSG_INFO, "nl80211: Failed to remove "
 				   "bridge %s: %s",