USB: cdc-acm: fix double free on probe failure

USB: cdc-acm: fix double free on probe failure

BugLink: https://bugs.launchpad.net/bugs/1923069
commit 7180495cb3d0e2a2860d282a468b4146c21da78f upstream.

If tty-device registration fails the driver copy of any Country
Selection functional descriptor would end up being freed twice; first
explicitly in the error path and then again in the tty-port destructor.

Drop the first erroneous free that was left when fixing a tty-port
resource leak.

Fixes: cae2bc768d17 ("usb: cdc-acm: Decrement tty port's refcount if probe() fail")
Cc: stable@vger.kernel.org      # 4.19
Cc: Jaejoong Kim <climbbb.kim@gmail.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210322155318.9837-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>