dmaengine: idxd: remove bus shutdown

Remove ->shutdown() function for the dsa bus as it does not do anything and
is not necessary.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162637462319.744545.10383189484257042066.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/idxd/sysfs.c

@@ -126,17 +126,11 @@ static int idxd_config_bus_remove(struct device *dev)
 	return 0;
 }
 
-static void idxd_config_bus_shutdown(struct device *dev)
-{
-	dev_dbg(dev, "%s called\n", __func__);
-}
-
 struct bus_type dsa_bus_type = {
 	.name = "dsa",
 	.match = idxd_config_bus_match,
 	.probe = idxd_config_bus_probe,
 	.remove = idxd_config_bus_remove,
-	.shutdown = idxd_config_bus_shutdown,
 };
 
 static struct idxd_device_driver dsa_drv = {