usb: roles: Link the switch to its connector

usb: roles: Link the switch to its connector

This is probable useful information to have in user space in
general, but it's primarily needed for the xHCI DbC (Debug
Capability). When xHCI DbC is being used, the USB port needs
to be muxed to the xHCI even in device role. In xHCI DbC mode,
the xHCI is the USB device controller.

Tested-by: Uday Bhat <uday.m.bhat@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20240213130018.3029991-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>