staging: vme: make vme_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the vme_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240208-bus_cleanup-staging2-v1-2-cfe906133a2c@marliere.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vme_user/vme.c

@@ -1970,7 +1970,7 @@ static void vme_bus_remove(struct device *dev)
 		driver->remove(vdev);
 }
 
-struct bus_type vme_bus_type = {
+const struct bus_type vme_bus_type = {
 	.name = "vme",
 	.match = vme_bus_match,
 	.probe = vme_bus_probe,

drivers/staging/vme_user/vme.h

@@ -81,7 +81,7 @@ struct vme_resource {
 	struct list_head *entry;
 };
 
-extern struct bus_type vme_bus_type;
+extern const struct bus_type vme_bus_type;
 
 /* Number of VME interrupt vectors */
 #define VME_NUM_STATUSID	256