edd: make kobj_type structure 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 definition to prevent
modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230227-kobj_type-firmware-edd-v1-1-c626afe5bd05@weissschuh.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/firmware/edd.c

@@ -608,7 +608,7 @@ static void edd_release(struct kobject * kobj)
 	kfree(dev);
 }
 
-static struct kobj_type edd_ktype = {
+static const struct kobj_type edd_ktype = {
 	.release	= edd_release,
 	.sysfs_ops	= &edd_attr_ops,
 };