firmware: dmi-sysfs: 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>
Link: https://lore.kernel.org/r/20230227-kobj_type-firmware-dmi-v1-1-d1131d4e7a2b@weissschuh.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/firmware/dmi-sysfs.c

@@ -304,7 +304,7 @@ static struct attribute *dmi_sysfs_sel_attrs[] = {
 };
 ATTRIBUTE_GROUPS(dmi_sysfs_sel);
 
-static struct kobj_type dmi_system_event_log_ktype = {
+static const struct kobj_type dmi_system_event_log_ktype = {
 	.release = dmi_entry_free,
 	.sysfs_ops = &dmi_sysfs_specialize_attr_ops,
 	.default_groups = dmi_sysfs_sel_groups,
@@ -563,7 +563,7 @@ static void dmi_sysfs_entry_release(struct kobject *kobj)
 	kfree(entry);
 }
 
-static struct kobj_type dmi_sysfs_entry_ktype = {
+static const struct kobj_type dmi_sysfs_entry_ktype = {
 	.release = dmi_sysfs_entry_release,
 	.sysfs_ops = &dmi_sysfs_attr_ops,
 	.default_groups = dmi_sysfs_entry_groups,