scsi: core: Constify the struct device_type usage

Since commit aed65af1 ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
scsi_host_type, scsi_target_type and scsi_dev_type variables to be constant
structures as well, placing it into read-only memory which can not be
modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240219-device_cleanup-scsi-v1-1-c5edf2afe178@marliere.netSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hosts.c

@@ -371,7 +371,7 @@ static void scsi_host_dev_release(struct device *dev)
 	kfree(shost);
 }
 
-static struct device_type scsi_host_type = {
+static const struct device_type scsi_host_type = {
 	.name =		"scsi_host",
 	.release =	scsi_host_dev_release,
 };

drivers/scsi/scsi_scan.c

@@ -412,7 +412,7 @@ static void scsi_target_dev_release(struct device *dev)
 	put_device(parent);
 }
 
-static struct device_type scsi_target_type = {
+static const struct device_type scsi_target_type = {
 	.name =		"scsi_target",
 	.release =	scsi_target_dev_release,
 };

drivers/scsi/scsi_sysfs.c

@@ -27,7 +27,7 @@
 #include "scsi_priv.h"
 #include "scsi_logging.h"
 
-static struct device_type scsi_dev_type;
+static const struct device_type scsi_dev_type;
 
 static const struct {
 	enum scsi_device_state	value;
@@ -1626,7 +1626,7 @@ int scsi_sysfs_add_host(struct Scsi_Host *shost)
 	return 0;
 }
 
-static struct device_type scsi_dev_type = {
+static const struct device_type scsi_dev_type = {
 	.name =		"scsi_device",
 	.release =	scsi_device_dev_release,
 	.groups =	scsi_sdev_attr_groups,