driver core: make platform_device_id table const

The platform ID table is normally const, force that by adding the attribute.
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

include/linux/platform_device.h

@@ -21,7 +21,7 @@ struct platform_device {
 	u32		num_resources;
 	struct resource	* resource;
 
-	struct platform_device_id	*id_entry;
+	const struct platform_device_id	*id_entry;
 
 	/* arch specific additions */
 	struct pdev_archdata	archdata;