gpib: lpvo_usb: fix memory leak on disconnect

The driver iterates over the registered USB interfaces during GPIB
attach and takes a reference to their USB devices until a match is
found. These references are never released which leads to a memory leak
when devices are disconnected.

Fix the leak by dropping the unnecessary references.

Fixes: fce7951 ("staging: gpib: Add LPVO DIY USB GPIB driver")
Cc: stable <stable@kernel.org> # 6.13
Cc: Dave Penkler <dpenkler@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260310105127.17538-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jhovold

drivers/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c

@@ -406,7 +406,7 @@ static int usb_gpib_attach(struct gpib_board *board, const struct gpib_board_con
 		for (j = 0 ; j < MAX_DEV ; j++) {
 			if ((assigned_usb_minors & 1 << j) == 0)
 				continue;
-			udev =	usb_get_dev(interface_to_usbdev(lpvo_usb_interfaces[j]));
+			udev = interface_to_usbdev(lpvo_usb_interfaces[j]);
 			device_path = kobject_get_path(&udev->dev.kobj, GFP_KERNEL);
 			match = gpib_match_device_path(&lpvo_usb_interfaces[j]->dev,
 						       config->device_path);
@@ -421,7 +421,7 @@ static int usb_gpib_attach(struct gpib_board *board, const struct gpib_board_con
 		for (j = 0 ; j < MAX_DEV ; j++) {
 			if ((assigned_usb_minors & 1 << j) == 0)
 				continue;
-			udev =	usb_get_dev(interface_to_usbdev(lpvo_usb_interfaces[j]));
+			udev = interface_to_usbdev(lpvo_usb_interfaces[j]);
 			DIA_LOG(1, "dev. %d: bus %d -> %d  dev: %d -> %d\n", j,
 				udev->bus->busnum, config->pci_bus, udev->devnum, config->pci_slot);
 			if (config->pci_bus == udev->bus->busnum &&