net: can: at91_can: world-writable sysfs files

Don't allow everybody to write to mb0_id file.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 2532b96..57d2ffb 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -1109,7 +1109,7 @@
 	return ret;
 }
 
-static DEVICE_ATTR(mb0_id, S_IWUGO | S_IRUGO,
+static DEVICE_ATTR(mb0_id, S_IWUSR | S_IRUGO,
 	at91_sysfs_show_mb0_id, at91_sysfs_set_mb0_id);
 
 static struct attribute *at91_sysfs_attrs[] = {