parport: make parport_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the parport_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>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240204-bus_cleanup-parport-v1-1-e6a0f756bbb8@marliere.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: rbmarliere

drivers/parport/share.c

@@ -130,7 +130,7 @@ static int parport_probe(struct device *dev)
 	return drv->probe(to_pardevice(dev));
 }
 
-static struct bus_type parport_bus_type = {
+static const struct bus_type parport_bus_type = {
 	.name = "parport",
 	.probe = parport_probe,
 };