device-dax: make dax_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the dax_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]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dave Jiang <[email protected]>

Author: rbmarliere

drivers/dax/bus.c

@@ -222,7 +222,7 @@ static void dax_bus_remove(struct device *dev)
 		dax_drv->remove(dev_dax);
 }
 
-static struct bus_type dax_bus_type = {
+static const struct bus_type dax_bus_type = {
 	.name = "dax",
 	.uevent = dax_bus_uevent,
 	.match = dax_bus_match,