usb: typec: class: Invalidate USB device pointers on partner unregistration

usb: typec: class: Invalidate USB device pointers on partner unregistration

To avoid using invalid USB device pointers after a Type-C partner
disconnects, this patch clears the pointers upon partner unregistration.
This ensures a clean state for future connections.

Cc: stable@vger.kernel.org
Fixes: 59de2a56d127 ("usb: typec: Link enumerated USB devices with Type-C partner")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20250321143728.4092417-3-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>