USB: gr_udc: remove dentry storage for debugfs file

There is no need to store the dentry pointer for a debugfs file that we
only use to remove it when the device goes away.  debugfs can do the
lookup for us instead, saving us some trouble, and making things smaller
overall.

Cc: Felipe Balbi <balbi@kernel.org>
Link: https://lore.kernel.org/r/20210527101426.3283214-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/gr_udc.c

@@ -207,14 +207,15 @@ DEFINE_SHOW_ATTRIBUTE(gr_dfs);
 static void gr_dfs_create(struct gr_udc *dev)
 {
 	const char *name = "gr_udc_state";
+	struct dentry *root;
 
-	dev->dfs_root = debugfs_create_dir(dev_name(dev->dev), usb_debug_root);
-	debugfs_create_file(name, 0444, dev->dfs_root, dev, &gr_dfs_fops);
+	root = debugfs_create_dir(dev_name(dev->dev), usb_debug_root);
+	debugfs_create_file(name, 0444, root, dev, &gr_dfs_fops);
 }
 
 static void gr_dfs_delete(struct gr_udc *dev)
 {
-	debugfs_remove_recursive(dev->dfs_root);
+	debugfs_remove(debugfs_lookup(dev_name(dev->dev), usb_debug_root));
 }
 
 #else /* !CONFIG_USB_GADGET_DEBUG_FS */

drivers/usb/gadget/udc/gr_udc.h

@@ -215,8 +215,6 @@ struct gr_udc {
 	struct list_head ep_list;
 
 	spinlock_t lock; /* General lock, a.k.a. "dev->lock" in comments */
-
-	struct dentry *dfs_root;
 };
 
 #define to_gr_udc(gadget)	(container_of((gadget), struct gr_udc, gadget))