[VOL-3054] Added flag -igmp to BBSim helm chart

Change-Id: I76cc726f98d2f46de4ea5b315e020fd8dafd8050
diff --git a/bbsim/values.yaml b/bbsim/values.yaml
index 26278c6..ae910f8 100644
--- a/bbsim/values.yaml
+++ b/bbsim/values.yaml
@@ -28,6 +28,7 @@
 pon: 1
 onu: 1
 auth: false
+igmp: false
 dhcp: false
 delay: 200
 c_tag: 900