usb: misc: usbio: Fix URB memory leak on submit failure

In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: Fix URB memory leak on submit failure When usb_submit_urb() fails in usbio_probe(), the previously allocated URB is never freed, causing a memory leak. Fix this by jumping to err_free_urb label to properly release the URB on the error path.