'Get embedded switch.
Get embedded switch by pci slot and validate pci has device mac
@param device_mac: device mac
@param pci_slot: pci slot'

def _get_emb_eswitch(self, device_mac, pci_slot):

    embedded_switch = self.pci_slot_map.get(pci_slot)
    if embedded_switch:
        used_device_mac = embedded_switch.get_pci_device(pci_slot)
        if (used_device_mac != device_mac):
            LOG.warning(_LW('device    pci    mismatch:    %(device_mac)s    -    %(pci_slot)s'), {'device_mac': device_mac, 'pci_slot': pci_slot})
            embedded_switch = None
    return embedded_switch
