CVE-2025-68734

In the Linux kernel, the following vulnerability has been resolved:

isdn: mISDN: hfcsusb: fix memory leak in hfcsusb_probe()

In hfcsusb_probe(), the memory allocated for ctrl_urb gets leaked when
setup_instance() fails with an error code. Fix that by freeing the urb
before freeing the hw structure. Also change the error paths to use the
goto ladder style.

Compile tested only. Issue found using a prototype static analysis tool.