Fix hostapd error path regression

Commit 354c903f8e47ae0fb41fb54ecc018e61d9573506 added setting of
driver_ap_teardown on the hostapd exit path without taking into account
that this may also be called on an error path where the interface has
not been initialized. Fix the resulting NULL pointer dereference to
allow hostapd to exit cleanly in error case.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

hostapd/main.c

@@ -729,6 +729,8 @@ int main(int argc, char *argv[])
 	hostapd_global_ctrl_iface_deinit(&interfaces);
 	/* Deinitialize all interfaces */
 	for (i = 0; i < interfaces.count; i++) {
+		if (!interfaces.iface[i])
+			continue;
 		interfaces.iface[i]->driver_ap_teardown =
 			!!(interfaces.iface[i]->drv_flags &
 			   WPA_DRIVER_FLAGS_AP_TEARDOWN_SUPPORT);