scsi: st: Make st_sysfs_class constant

Since commit 43a7206b ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the st_sysfs_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240302-class_cleanup-scsi-v1-5-b9096b990e27@marliere.netSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/st.c

@@ -87,7 +87,7 @@ static int try_rdio = 1;
 static int try_wdio = 1;
 static int debug_flag;
 
-static struct class st_sysfs_class;
+static const struct class st_sysfs_class;
 static const struct attribute_group *st_dev_groups[];
 static const struct attribute_group *st_drv_groups[];
 
@@ -4438,7 +4438,7 @@ static void scsi_tape_release(struct kref *kref)
 	return;
 }
 
-static struct class st_sysfs_class = {
+static const struct class st_sysfs_class = {
 	.name = "scsi_tape",
 	.dev_groups = st_dev_groups,
 };