sparc: vio: make vio_bus_type const

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

Cc: Greg Kroah-Hartman <[email protected]>
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Sam Ravnborg <[email protected]>
Signed-off-by: Andreas Larsson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: rbmarliere

arch/sparc/kernel/vio.c

@@ -149,7 +149,7 @@ static struct attribute *vio_dev_attrs[] = {
  };
 ATTRIBUTE_GROUPS(vio_dev);
 
-static struct bus_type vio_bus_type = {
+static const struct bus_type vio_bus_type = {
 	.name		= "vio",
 	.dev_groups	= vio_dev_groups,
 	.uevent         = vio_hotplug,