commit 4fe9f8e2 upstream.

When a device is unplugged, wait for all processes that have opened the device
to close before deallocating the device.
Signed-off-by: Ratan Nalumasu <ratan@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>