i40e: Fix sparse error: 'vsi->netdev' could be null

Remove vsi->netdev->name from the trace.
This is redundant information. With the devinfo trace, the adapter
is already identifiable.

Previously following error was produced when compiling against sparse.
i40e_main.c:2571 i40e_sync_vsi_filters() error:
	we previously assumed 'vsi->netdev' could be null (see line 2323)

Fixes: b603f9dc ("i40e: Log info when PF is entering and leaving Allmulti mode.")
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -2560,8 +2560,7 @@ int i40e_sync_vsi_filters(struct i40e_vsi *vsi)
 				 i40e_stat_str(hw, aq_ret),
 				 i40e_aq_str(hw, hw->aq.asq_last_status));
 		} else {
-			dev_info(&pf->pdev->dev, "%s is %s allmulti mode.\n",
-				 vsi->netdev->name,
+			dev_info(&pf->pdev->dev, "%s allmulti mode.\n",
 				 cur_multipromisc ? "entering" : "leaving");
 		}
 	}