device property: Constify argument to pset fwnode backend

Internally constify pset fwnode backend. Do not touch the pset fwnode
operations yet.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 file changed