[sonic-cfggen] Allow cfggen to work on system without ports

Signed-off-by: liora <[email protected]>

Author: liorghub

src/sonic-config-engine/sonic-cfggen

@@ -317,6 +317,9 @@ def main():
         if args.port_config is None:
             args.port_config = device_info.get_path_to_port_config_file(hwsku)
         (ports, _, _) = get_port_config(hwsku, platform, args.port_config, asic_id)
+        if ports is None:
+            print('Failed to get port config', file=sys.stderr)
+            sys.exit(1)
         deep_update(data, {'PORT': ports})
 
         brkout_table = get_breakout_mode(hwsku, platform, args.port_config)