i40e: Fix the Tx ring qset handle when DCB reconfigures

When DCB is reconfigured to single TC the driver did not reset the
Tx ring Qset handle to the correct mapping; which caused Tx queue
disable timeouts.

Change-ID: I4da5915ec92a83c281b478d653fae6ef1b72edfe
Signed-off-by: NNeerav Parikh <neerav.parikh@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

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

@@ -2689,8 +2689,15 @@ static void i40e_vsi_config_dcb_rings(struct i40e_vsi *vsi)
 	u16 qoffset, qcount;
 	int i, n;
 
-	if (!(vsi->back->flags & I40E_FLAG_DCB_ENABLED))
-		return;
+	if (!(vsi->back->flags & I40E_FLAG_DCB_ENABLED)) {
+		/* Reset the TC information */
+		for (i = 0; i < vsi->num_queue_pairs; i++) {
+			rx_ring = vsi->rx_rings[i];
+			tx_ring = vsi->tx_rings[i];
+			rx_ring->dcb_tc = 0;
+			tx_ring->dcb_tc = 0;
+		}
+	}
 
 	for (n = 0; n < I40E_MAX_TRAFFIC_CLASS; n++) {
 		if (!(vsi->tc_config.enabled_tc & (1 << n)))