i40e: fix panic due to too-early Tx queue enable

This fixes the panic under traffic load when resetting.  This issue
could also show up if/whenever there is a Tx-timeout.

Change-ID: Ie393a1f17fd5d962e56fc3bfe784899ef25402f5
Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Tested-by: NJim Young <jamesx.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

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

@@ -5289,7 +5289,7 @@ static void i40e_fdir_reinit_subtask(struct i40e_pf *pf)
  **/
 static void i40e_vsi_link_event(struct i40e_vsi *vsi, bool link_up)
 {
-	if (!vsi)
+	if (!vsi || test_bit(__I40E_DOWN, &vsi->state))
 		return;
 
 	switch (vsi->type) {