libvhost-user: fix bad vu_log_write

Mark dirty as page, the step of each call is 1.
Signed-off-by: NLi Feng <fengli@smartx.com>
Message-Id: <20190420091016.213160-1-fengli@smartx.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

contrib/libvhost-user/libvhost-user.c

@@ -433,7 +433,7 @@ vu_log_write(VuDev *dev, uint64_t address, uint64_t length)
     page = address / VHOST_LOG_PAGE;
     while (page * VHOST_LOG_PAGE < address + length) {
         vu_log_page(dev->log_table, page);
-        page += VHOST_LOG_PAGE;
+        page += 1;
     }
 
     vu_log_kick(dev);