Introduce osmux support for msc,bsc,mgw

Change-Id: Ief3518e77650f2cddb48357b07fe95346e46ee1b
diff --git a/src/osmo_gsm_tester/templates/osmo-msc.cfg.tmpl b/src/osmo_gsm_tester/templates/osmo-msc.cfg.tmpl
index b370d5e..31c57d3 100644
--- a/src/osmo_gsm_tester/templates/osmo-msc.cfg.tmpl
+++ b/src/osmo_gsm_tester/templates/osmo-msc.cfg.tmpl
@@ -28,6 +28,7 @@
  mgw local-ip ${msc.ip_address.addr}
  mgw endpoint-range 1 31
  mgw bts-base 8000
+ osmux ${msc.use_osmux}
  assign-tmsi
  cs7-instance-iu 0
  cs7-instance-a 0