ice: Fix a few null pointer dereference issues

1) When ice_ena_msix_range() fails to reserve vectors, a devm_kfree()
   warning was seen in the error flow path. So check pf->irq_tracker
   before use in ice_clear_interrupt_scheme().

2) In ice_vsi_cfg(), check vsi->netdev before use.

3) In ice_get_link_status, check link_up before use.
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

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

@@ -1483,7 +1483,7 @@ enum ice_status ice_get_link_status(struct ice_port_info *pi, bool *link_up)
 	struct ice_phy_info *phy_info;
 	enum ice_status status = 0;
 
-	if (!pi)
+	if (!pi || !link_up)
 		return ICE_ERR_PARAM;
 
 	phy_info = &pi->phy;

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

@@ -3257,8 +3257,10 @@ static void ice_clear_interrupt_scheme(struct ice_pf *pf)
 	if (test_bit(ICE_FLAG_MSIX_ENA, pf->flags))
 		ice_dis_msix(pf);
 
+	if (pf->irq_tracker) {
 		devm_kfree(&pf->pdev->dev, pf->irq_tracker);
 		pf->irq_tracker = NULL;
+	}
 }
 
 /**
@@ -4112,11 +4114,12 @@ static int ice_vsi_cfg(struct ice_vsi *vsi)
 {
 	int err;
 
+	if (vsi->netdev) {
 		ice_set_rx_mode(vsi->netdev);
-
 		err = ice_restore_vlan(vsi);
 		if (err)
 			return err;
+	}
 
 	err = ice_vsi_cfg_txqs(vsi);
 	if (!err)