net: eepro100: fix memory leak in device uninit

The exit dispatch of eepro100 network card device doesn't free
the 's->vmstate' field which was allocated in device realize thus
leading a host memory leak. This patch avoid this.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/eepro100.c

@@ -1843,6 +1843,7 @@ static void pci_nic_uninit(PCIDevice *pci_dev)
     EEPRO100State *s = DO_UPCAST(EEPRO100State, dev, pci_dev);
 
     vmstate_unregister(&pci_dev->qdev, s->vmstate, s);
+    g_free(s->vmstate);
     eeprom93xx_free(&pci_dev->qdev, s->eeprom);
     qemu_del_nic(s->nic);
 }