usb: typec: tipd: fix uninitialized typec_partner_desc in cd321x_update_work()

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

usb: typec: tipd: fix uninitialized typec_partner_desc in cd321x_update_work()

cd321x_update_work() passes a stack-allocated typec_partner_desc to
typec_register_partner() after initializing only usb_pd, accessory and
identity.

typec_register_partner() copies attach and deattach from the descriptor
into the partner. With those fields left unset, garbage function pointers
may be stored and later invoked from typec_partner_link_device() when a USB
device is linked to the port. Uninitialized pd_revision and usb_capability
similarly leak stack data through partner sysfs.

Zero-initialize the descriptor so optional callbacks remain NULL and the
remaining fields are zero.