device property: fix potential NULL pointer dereference

In device_add_property_set() we check pset parameter for a NULL, but few lines
later we do a pointer arithmetic without check that will crash kernel in the
set_secondary_fwnode().

Here we check if pset parameter is NULL and return immediately.

Fixes: 16ba08d5c9 (device property: Introduce firmware node type for platform data)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/property.c

@@ -27,9 +27,10 @@
  */
 void device_add_property_set(struct device *dev, struct property_set *pset)
 {
-	if (pset)
-		pset->fwnode.type = FWNODE_PDATA;
+	if (!pset)
+		return;
 
+	pset->fwnode.type = FWNODE_PDATA;
 	set_secondary_fwnode(dev, &pset->fwnode);
 }
 EXPORT_SYMBOL_GPL(device_add_property_set);