usb: typec: ucsi: Only assign the identity structure if the PPM supports it

This will make sure that the identity sysfs attribute files
are kept hidden if the UCSI interface doesn't support
reading the USB Power Delivery messages.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Link: https://lore.kernel.org/r/20240816135859.3499351-4-heikki.krogerus@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>