ipack: make ipack_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the ipack_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>
Acked-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Link: https://lore.kernel.org/r/20240204-bus_cleanup-ipack-v1-1-aef5e8f84d01@marliere.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/ipack/ipack.c

@@ -187,7 +187,7 @@ static struct attribute *ipack_attrs[] = {
 };
 ATTRIBUTE_GROUPS(ipack);
 
-static struct bus_type ipack_bus_type = {
+static const struct bus_type ipack_bus_type = {
 	.name      = "ipack",
 	.probe     = ipack_bus_probe,
 	.match     = ipack_bus_match,