iavf: Fix missing check for running netdev

The driver was queueing reset_task regardless of the netdev
state.

Do not queue the reset task in iavf_change_mtu if netdev
is not running.

Fixes: fdd4044f ("iavf: Remove timer for work triggering, use delaying work instead")
Signed-off-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Phani Burra <phani.r.burra@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -3905,8 +3905,11 @@ static int iavf_change_mtu(struct net_device *netdev, int new_mtu)
 		iavf_notify_client_l2_params(&adapter->vsi);
 		adapter->flags |= IAVF_FLAG_SERVICE_CLIENT_REQUESTED;
 	}
+
+	if (netif_running(netdev)) {
 		adapter->flags |= IAVF_FLAG_RESET_NEEDED;
 		queue_work(iavf_wq, &adapter->reset_task);
+	}
 
 	return 0;
 }