device property: Constify device_get_match_data()

Constify device_get_match_data() as OF and ACPI variants return
constant value.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index 4fa1a48..4fe8f28 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -73,8 +73,8 @@ struct fwnode_operations {
 	struct fwnode_handle *(*get)(struct fwnode_handle *fwnode);
 	void (*put)(struct fwnode_handle *fwnode);
 	bool (*device_is_available)(const struct fwnode_handle *fwnode);
-	void *(*device_get_match_data)(const struct fwnode_handle *fwnode,
-				       const struct device *dev);
+	const void *(*device_get_match_data)(const struct fwnode_handle *fwnode,
+					     const struct device *dev);
 	bool (*property_present)(const struct fwnode_handle *fwnode,
 				 const char *propname);
 	int (*property_read_int_array)(const struct fwnode_handle *fwnode,