The calculation of bytes_xfer in qemu_put_buffer() is wrong

In qemu_put_buffer(), bytes_xfer += size is wrong, it will be more
than expected, and should be bytes_xfer += l.
Signed-off-by: Nzhangmin <zhangmin6@huawei.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

savevm.c

@@ -794,7 +794,7 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
         if (l > size)
             l = size;
         memcpy(f->buf + f->buf_index, buf, l);
-        f->bytes_xfer += size;
+        f->bytes_xfer += l;
         if (f->ops->writev_buffer) {
             add_to_iovec(f, f->buf + f->buf_index, l);
         }