staging: vc04_services: vchiq_arm: make vchiq_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the vchiq_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-v1-1-cfe906133a2c@marliere.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c

@@ -37,7 +37,7 @@ static int vchiq_bus_probe(struct device *dev)
 	return driver->probe(device);
 }
 
-struct bus_type vchiq_bus_type = {
+const struct bus_type vchiq_bus_type = {
 	.name   = "vchiq-bus",
 	.match  = vchiq_bus_type_match,
 	.uevent = vchiq_bus_uevent,

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h

@@ -34,7 +34,7 @@ static inline struct vchiq_driver *to_vchiq_driver(struct device_driver *d)
 	return container_of(d, struct vchiq_driver, driver);
 }
 
-extern struct bus_type vchiq_bus_type;
+extern const struct bus_type vchiq_bus_type;
 
 struct vchiq_device *
 vchiq_device_register(struct device *parent, const char *name);