dviasm.py: preserve original id byte (prepare for nptex)

dviasm.py

@@ -6,7 +6,7 @@
 # Copyright (C) 2007-2008 by Jin-Hwan Cho <[email protected]>
 # Copyright (C) 2011-2017 by Khaled Hosny <[email protected]>
 # Copyright (C) 2019      by Arthur Reutenauer <[email protected]>
-# Copyright (C) 2019-2022 by Hironobu Yamashita <[email protected]>
+# Copyright (C) 2019-2023 by Hironobu Yamashita <[email protected]>
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -315,8 +315,7 @@ def ProcessPreamble(self, fp):
     id = GetByte(fp)
     if not ValidID(id):
       warning("ID byte is %d; use the default %d!" % (id, DVI_ID))
-    else:
-      self.id = id
+    self.id = id
     numerator = SignedQuad(fp)
     if numerator <= 0:
       warning('numerator is %d; use the default 25400000!' % numerator)