[VOL-5241]: Add Zyxel to ONU Vendor list

Change-Id: I4dc8f0efd1a85cad001e9987d68859070f0f9d4b
diff --git a/voltha-adapter-openonu/values.yaml b/voltha-adapter-openonu/values.yaml
index dfc9dc6..3a80446 100644
--- a/voltha-adapter-openonu/values.yaml
+++ b/voltha-adapter-openonu/values.yaml
@@ -108,6 +108,8 @@
   - ARCA
   - AVMG
   - ZYWN
+  - ZYXE
+  - ZYSG
 
 # Expose the golang pprof webserver, if enabled
 profiler: