gpib: lpvo_usb: fix memory leak on disconnect

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: fce79512a96a ("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>