vhost: rename vhost_work_dev_flush

vhost: rename vhost_work_dev_flush

This patch renames vhost_work_dev_flush to just vhost_dev_flush to
relfect that it flushes everything on the device and that drivers
don't know/care that polls are based on vhost_works. Drivers just
flush the entire device and polls, and works for vhost-scsi
management TMFs and IO net virtqueues, etc all are flushed.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20220517180850.198915-9-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>