platform/x86: intel_cht_int33fe: Use new API to gain access to the role switch

The driver for the Intel USB role mux now always supplies
software node for the role switch, so no longer checking
that, and never creating separate node for the role switch.
From now on using software_node_find_by_name() function to
get the handle to the USB role switch.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>