vhost: fix typos in comment

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 073d06a..2af44b7 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -102,7 +102,7 @@
 	 * flush the vhost_work instead of synchronize_rcu. Therefore readers do
 	 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
 	 * vhost_work execution acts instead of rcu_read_lock() and the end of
-	 * vhost_work execution acts instead of rcu_read_lock().
+	 * vhost_work execution acts instead of rcu_read_unlock().
 	 * Writers use virtqueue mutex. */
 	void __rcu *private_data;
 	/* Log write descriptors */