tifm: constify the struct tifm_bus_type usage

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

Signed-off-by: Kunwu Chan <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/tifm_core.c

···
 };
 ATTRIBUTE_GROUPS(tifm_dev);
 
-static struct bus_type tifm_bus_type = {
+static const struct bus_type tifm_bus_type = {
 	.name      = "tifm",
 	.dev_groups = tifm_dev_groups,
 	.match     = tifm_bus_match,