sgsnemu: Add --no-tx-gpdu-seq option to suppress transmission of G-PDU sequence numbers

Related: OS#2519
Change-Id: Idc650d896f0f72329090b56a37d9c16359294860
diff --git a/sgsnemu/cmdline.ggo b/sgsnemu/cmdline.ggo
index 4fcc64a..a2681f1 100644
--- a/sgsnemu/cmdline.ggo
+++ b/sgsnemu/cmdline.ggo
@@ -60,4 +60,4 @@
 option  "pingsize"     - "Number of ping data bytes"      int default="56" no
 option  "pingcount"    - "Number of ping req to send"     int default="0" no
 option  "pingquiet"    - "Do not print ping packet info"  flag off
-
+option  "no-tx-gpdu-seq" - "Don't transmit G-PDU sequence nums"   flag    off