ubifs: make kobj_type structures constant

Since commit ee6d3dd4 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definitions to prevent
modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/sysfs.c

@@ -74,13 +74,13 @@ static const struct sysfs_ops ubifs_attr_ops = {
 	.show	= ubifs_attr_show,
 };
 
-static struct kobj_type ubifs_sb_ktype = {
+static const struct kobj_type ubifs_sb_ktype = {
 	.default_groups	= ubifs_groups,
 	.sysfs_ops	= &ubifs_attr_ops,
 	.release	= ubifs_sb_release,
 };
 
-static struct kobj_type ubifs_ktype = {
+static const struct kobj_type ubifs_ktype = {
 	.sysfs_ops	= &ubifs_attr_ops,
 };