mtd: do not use plain 0 as NULL

The first 3 arguments of 'mtd_device_parse_register()' are pointers,
but many callers pass '0' instead of 'NULL'. Fix this globally. Thanks
to coccinelle for making it easy to do with the following semantic patch:

 @@
 expression mtd, types, parser_data, parts, nr_parts;
 @@
 (
 -mtd_device_parse_register(mtd, 0, parser_data, parts, nr_parts)
 +mtd_device_parse_register(mtd, NULL, parser_data, parts, nr_parts)
 |
 -mtd_device_parse_register(mtd, types, 0, parts, nr_parts)
 +mtd_device_parse_register(mtd, types, NULL, parts, nr_parts)
 |
 -mtd_device_parse_register(mtd, types, parser_data, 0, nr_parts)
 +mtd_device_parse_register(mtd, types, parser_data, NULL, nr_parts)
 )

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/maps/rbtx4939-flash.c b/drivers/mtd/maps/rbtx4939-flash.c
index 3da63fc..6f52e1f 100644
--- a/drivers/mtd/maps/rbtx4939-flash.c
+++ b/drivers/mtd/maps/rbtx4939-flash.c
@@ -102,8 +102,8 @@
 	info->mtd->owner = THIS_MODULE;
 	if (err)
 		goto err_out;
-	err = mtd_device_parse_register(info->mtd, NULL, 0,
-			pdata->parts, pdata->nr_parts);
+	err = mtd_device_parse_register(info->mtd, NULL, NULL, pdata->parts,
+					pdata->nr_parts);
 
 	if (err)
 		goto err_out;