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 <[e-mail]>
Signed-off-by: "Ricardo B. Marliere" <[e-mail]>
Acked-by: Vaibhav Gupta <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/ipack/ipack.c

···
 };
 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,