block: constify struct part_type part_type

The struct is never modified so it can be const.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230419-const-partition-v3-2-4e14e48be367@weissschuh.netSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/partitions/core.c

@@ -256,7 +256,7 @@ static int part_uevent(const struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
-struct device_type part_type = {
+const struct device_type part_type = {
 	.name		= "partition",
 	.groups		= part_attr_groups,
 	.release	= part_release,

include/linux/blkdev.h

@@ -41,7 +41,7 @@ struct blk_stat_callback;
 struct blk_crypto_profile;
 
 extern const struct device_type disk_type;
-extern struct device_type part_type;
+extern const struct device_type part_type;
 extern struct class block_class;
 
 /*