ice: use irq_num var in ice_vsi_req_irq_msix

Someone went through the effort of making this a variable so let's use
it instead of recalculating it again.
Signed-off-by: NAlan Brady <alan.brady@intel.com>
Signed-off-by: NAnirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ice/ice_main.c

@@ -1248,10 +1248,9 @@ static int ice_vsi_req_irq_msix(struct ice_vsi *vsi, char *basename)
 			/* skip this unused q_vector */
 			continue;
 		}
-		err = devm_request_irq(&pf->pdev->dev,
-				       pf->msix_entries[base + vector].vector,
-				       vsi->irq_handler, 0, q_vector->name,
-				       q_vector);
+		err = devm_request_irq(&pf->pdev->dev, irq_num,
+				       vsi->irq_handler, 0,
+				       q_vector->name, q_vector);
 		if (err) {
 			netdev_err(vsi->netdev,
 				   "MSIX request_irq failed, error: %d\n", err);