[load_minigraph]: Avoid starting PFCWD for EPMS devicetype (sonic-net#1552)

Author: sumukhatv

config/main.py

@@ -1187,7 +1187,7 @@ def load_minigraph(db, no_service_restart):
 
     # get the device type
     device_type = _get_device_type()
-    if device_type != 'MgmtToRRouter':
+    if device_type != 'MgmtToRRouter' and device_type != 'EPMS':
         clicommon.run_command("pfcwd start_default", display_cmd=True)
 
     # Update SONiC environmnet file