[vmxnet3] Check for ioremap() failures

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/vmxnet3.c

 	/* Map PCI BARs */
 	vmxnet->pt = ioremap ( pci_bar_start ( pci, VMXNET3_PT_BAR ),
 			       VMXNET3_PT_LEN );
+	if ( ! vmxnet->pt ) {
+		rc = -ENODEV;
+		goto err_ioremap_pt;
+	}
 	vmxnet->vd = ioremap ( pci_bar_start ( pci, VMXNET3_VD_BAR ),
 			       VMXNET3_VD_LEN );
+	if ( ! vmxnet->vd ) {
+		rc = -ENODEV;
+		goto err_ioremap_vd;
+	}
 
 	/* Version check */
 	if ( ( rc = vmxnet3_check_version ( vmxnet ) ) != 0 )
  err_reset:
  err_check_version:
 	iounmap ( vmxnet->vd );
+ err_ioremap_vd:
 	iounmap ( vmxnet->pt );
+ err_ioremap_pt:
 	netdev_nullify ( netdev );
 	netdev_put ( netdev );
  err_alloc_etherdev: