target/configfs: allocate only 6 slots for dev_cg->default_groups

Only slots 0-5 are used so 6 slots should be enough. I don't see anyone
writting anything else than NULL into ->default_groups[5] so a "late"
initialisation should not happen here.

(nab: Fix up minor apply breakage in for-next)
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_configfs.c

@@ -2496,7 +2496,7 @@ static struct config_group *target_core_make_subdev(
 
 	dev_cg = &dev->dev_group;
 
-	dev_cg->default_groups = kzalloc(sizeof(struct config_group *) * 7,
+	dev_cg->default_groups = kzalloc(sizeof(struct config_group *) * 6,
 			GFP_KERNEL);
 	if (!dev_cg->default_groups)
 		goto out_free_device;