[luxembourg] Add eth2 description for granduc-12

Signed-off-by: Hyacinthe Cartiaux <hyacinthe.cartiaux@uni.lu>

data/grid5000/sites/luxembourg/clusters/granduc/nodes/granduc-12.json

@@ -54,7 +54,7 @@
       "driver": "ixgbe",
       "enabled": false,
       "interface": "Ethernet",
-      "mac": null,
+      "mac": "00:1b:21:34:e1:1d",
       "rate": 10000000000
     }
   ],

generators/input/luxembourg-granduc.yaml

@@ -432,6 +432,9 @@ granduc-12:
     eth1:
       mac: 00:19:b9:f2:0e:12
       ip: 172.18.176.12
+    eth2:
+      mac: 00:1b:21:34:e1:1d
+      ip: 192.168.14.12
   chassis:
     serial_number: 50W883J
     manufacturer: Dell Inc.