mtd: rawnand: nandsim: Keep track of the created debugfs entries

Debugfs entries should be removed in the error path, so first, keep
track of them.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200525085851.17682-6-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/nandsim.c

@@ -353,6 +353,9 @@ struct nandsim {
 	void *file_buf;
 	struct page *held_pages[NS_MAX_HELD_PAGES];
 	int held_cnt;
+
+	/* debugfs entry */
+	struct dentry *dent;
 };
 
 /*
@@ -495,7 +498,6 @@ DEFINE_SHOW_ATTRIBUTE(ns);
 static int ns_debugfs_create(struct nandsim *ns)
 {
 	struct dentry *root = nsmtd->dbg.dfs_dir;
-	struct dentry *dent;
 
 	/*
 	 * Just skip debugfs initialization when the debugfs directory is
@@ -508,9 +510,9 @@ static int ns_debugfs_create(struct nandsim *ns)
 		return 0;
 	}
 
-	dent = debugfs_create_file("nandsim_wear_report", 0400, root, ns,
+	ns->dent = debugfs_create_file("nandsim_wear_report", 0400, root, ns,
 				       &ns_fops);
-	if (IS_ERR_OR_NULL(dent)) {
+	if (IS_ERR_OR_NULL(ns->dent)) {
 		NS_ERR("cannot create \"nandsim_wear_report\" debugfs entry\n");
 		return -1;
 	}