bnxt_en: Device serial number is supported only for PFs.

Don't read DSN on VFs that do not have the PCI capability.

Fixes: 03213a99 ("bnxt: move bp->switch_id initialization to PF probe")
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -10725,11 +10725,12 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto init_err_pci_clean;
 	}
 
+	if (BNXT_PF(bp)) {
 		/* Read the adapter's DSN to use as the eswitch switch_id */
 		rc = bnxt_pcie_dsn_get(bp, bp->switch_id);
 		if (rc)
 			goto init_err_pci_clean;
-
+	}
 	bnxt_hwrm_func_qcfg(bp);
 	bnxt_hwrm_vnic_qcaps(bp);
 	bnxt_hwrm_port_led_qcaps(bp);