USB: host: uhci: remove dentry pointer for debugfs

There is no need to keep the dentry pointer around for the created
debugfs file, as it is only needed when removing it from the system.
When it is to be removed, ask debugfs itself for the pointer, to save on
storage and make things a bit simpler.

And, no one noticed that a __maybe_unused dentry * in uhci_start()
really was unused, so remove that as it's obviously not needed, and
hasn't been for quite some time.

Cc: Alan Stern <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/uhci-hcd.c

···
 	uhci->is_initialized = 0;
 	spin_unlock_irq(&uhci->lock);
 
-	debugfs_remove(uhci->dentry);
+	debugfs_remove(debugfs_lookup(uhci_to_hcd(uhci)->self.bus_name,
+				      uhci_debugfs_root));
 
 	for (i = 0; i < UHCI_NUM_SKELQH; i++)
 		uhci_free_qh(uhci, uhci->skelqh[i]);
···
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
 	int retval = -EBUSY;
 	int i;
-	struct dentry __maybe_unused *dentry;
 
 	hcd->uses_new_polling = 1;
 	/* Accept arbitrarily long scatter-gather lists */
···
 	init_waitqueue_head(&uhci->waitqh);
 
 #ifdef UHCI_DEBUG_OPS
-	uhci->dentry = debugfs_create_file(hcd->self.bus_name,
-					   S_IFREG|S_IRUGO|S_IWUSR,
-					   uhci_debugfs_root, uhci,
-					   &uhci_debug_operations);
+	debugfs_create_file(hcd->self.bus_name, S_IFREG|S_IRUGO|S_IWUSR,
+			    uhci_debugfs_root, uhci, &uhci_debug_operations);
 #endif
 
 	uhci->frame = dma_alloc_coherent(uhci_dev(uhci),
···
 			uhci->frame, uhci->frame_dma_handle);
 
 err_alloc_frame:
-	debugfs_remove(uhci->dentry);
+	debugfs_remove(debugfs_lookup(hcd->self.bus_name, uhci_debugfs_root));
 
 	return retval;
 }

drivers/usb/host/uhci-hcd.h

···
  * The full UHCI controller information:
  */
 struct uhci_hcd {
-
-	/* debugfs */
-	struct dentry *dentry;
-
 	/* Grabbed from PCI */
 	unsigned long io_addr;