usb: typec: ucsi: Optimise ucsi_unregister()

There is no need to reset the PPM when the interface is
unregistered. Quietly silencing the notifications and then
unregistering everything is enough. This speeds up
ucsi_unregister() a lot.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Ajay Gupta <ajayg@nvidia.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191104142435.29960-19-heikki.krogerus@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/ucsi/ucsi.c

@@ -1045,15 +1045,14 @@ EXPORT_SYMBOL_GPL(ucsi_register);
  */
 void ucsi_unregister(struct ucsi *ucsi)
 {
-	u64 command;
+	u64 cmd = UCSI_SET_NOTIFICATION_ENABLE;
 	int i;
 
 	/* Make sure that we are not in the middle of driver initialization */
 	cancel_work_sync(&ucsi->work);
 
-	/* Disable everything except command complete notification */
-	command = UCSI_SET_NOTIFICATION_ENABLE | UCSI_ENABLE_NTFY_CMD_COMPLETE;
-	ucsi_send_command(ucsi, command, NULL, 0);
+	/* Disable notifications */
+	ucsi->ops->async_write(ucsi, UCSI_CONTROL, &cmd, sizeof(cmd));
 
 	for (i = 0; i < ucsi->cap.num_connectors; i++) {
 		cancel_work_sync(&ucsi->connector[i].work);
@@ -1063,8 +1062,6 @@ void ucsi_unregister(struct ucsi *ucsi)
 		typec_unregister_port(ucsi->connector[i].port);
 	}
 
-	ucsi_reset_ppm(ucsi);
-
 	kfree(ucsi->connector);
 }
 EXPORT_SYMBOL_GPL(ucsi_unregister);