Revert "driver core: shut down devices asynchronously"

This reverts commit 8064952c65.

The series is being reverted before -rc1 as there are still reports of
lockups on shutdown, so it's not quite ready for "prime time."

Reported-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Link: https://lore.kernel.org/r/ZvMkkhyJrohaajuk@skv.local
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Jeffery <djeffery@redhat.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/device/driver.h

@@ -56,7 +56,6 @@ enum probe_type {
  * @mod_name:	Used for built-in modules.
  * @suppress_bind_attrs: Disables bind/unbind via sysfs.
  * @probe_type:	Type of the probe (synchronous or asynchronous) to use.
- * @async_shutdown_enable: Enables devices to be shutdown asynchronously.
  * @of_match_table: The open firmware table.
  * @acpi_match_table: The ACPI match table.
  * @probe:	Called to query the existence of a specific device,
@@ -103,7 +102,6 @@ struct device_driver {
 
 	bool suppress_bind_attrs;	/* disables bind/unbind via sysfs */
 	enum probe_type probe_type;
-	bool async_shutdown_enable;
 
 	const struct of_device_id	*of_match_table;
 	const struct acpi_device_id	*acpi_match_table;